Energy conservation by dimmed LED lighting

Energy conservation is still a desirable objective for the lighting sector. An adequate means for implementation is, for example, the adjustment of the illumination intensity in accordance with the respective requirements and circumstances. For instance, the LED lighting could either be dimmed during the day when the sun is shining or increased when darkness sets in.

The FRIWO DIMMboxes or Light Control Box offer technically advanced solutions in a slim design of 21 x 30 x 153 mm (H x B x L). The DIMMboxes allow flicker-free dimming both in constant-current mode (CC) as well as in constant mode (CV) by a pulse width modulation (PWM) with a frequency of 600 Hz. With the Light Control Box, designed for CC mode, lighting control is effected by linear lowering of the output current. Both systems offer a control via DALI/PUSH-DIM or 1 – 10 V signal. The Light Control Box also comes with a PWM input for the connection of external sensors like motion or brightness sensors. An auxiliary voltage of 12 V for the sensors is also provided.

Optimize your LED lighting with FRIWO’s DIMMboxes or Light Control Box and save energy.

FRIWO now successfully certified according to DIN EN ISO 13485

An additional quality promise to medical technology: After FRIWO has successfully passed the auditing by TÜV Nord in December 2017, the German manufacturer of power supplies has received the official certification according to DIN EN ISO 13485:2012. Backed by this independent authority’s certification, FRIWO’s customers can rely upon that quality management system and development processes within the company do comply with the high regulatory requirements.

“With the certification according to ISO 13485, our teams have reached another milestone we are extremely proud of. By this demanding certification we prove to be a reliable partner for medical technology industry and we strengthen our customers’ confidence in our performance and efficiency”, states Rolf Schwirz, Managing Director for FRIWO, with satisfaction.

DIN EN ISO 13485 defines regulatory requirements for a comprehensive management system of medical product manufacturers. As an internationally accepted standard, this regulation contains guidelines concerning construction and development, production, installation, maintenance, and distribution. This certification imposes high levels for the exact adherence to all process steps. Special attention is paid to consequent and complete documentation and risk management; not only concerning minimization of risks, but also an optimal traceability of products and components.

Examination and assessment of lithium-ion battery life

For many applications the use of lithium-ion cells requires an estimate of the expected battery pack’s life. This consideration is an important aspect not only for direct application, but also for the definition of service intervals, and last but not least for storage.
The life of a battery pack is determined essentially by two factors:
Cyclical and calendrical aging. This paper provides an overview of these two aging processes and their significance.

Service life factors of battery packs
The service life of a battery pack is defined by the cyclical life (how often can a battery be charged and discharged?) and the calendrical life (how much capacity does the battery lose due to aging effects?). In general, with regular use of the application, the number of cycles determines the end of life of the battery because charging and discharging processes damage the battery faster than aging processes.

Figure 1: Life span of a lithium-ion battery pack
Data sheets of the cells used provide the first clues as to the life span of a battery pack. Here you will find information on the number of cycles and storage, which can only serve as first indicators of the actual life: Especially the number of cycles indicated in the data sheets depends on a variety of marginal and side conditions, which often deviate from the real operating conditions of the specific application.

Factor 1: Cyclical aging
Cyclical aging describes the proportion of aging that results from the battery use (repeated charging and discharging). This can be attributed to chemical and mechanical wear effects, including, for example, thermal expansion or dendrite growth.
For cyclical aging, the depth of discharge is a crucial factor. A deep discharge stresses the material chemically and mechanically, reducing the number of possible cycles. This correlation, however, is not linear, so halving the depth of discharge can double the number of possible cycles.
With a depth of discharge between 90 % and 100 %, the cyclical aging is particularly high, which is why this area is used only in exceptional cases. Generally, applications work at discharge depths of ≤ 90 %.
In addition to a limited depth of discharge, the number of possible cycles can also be influenced by regulating the end-of-charge voltage. Thus limitations of the charging voltage to a value below the nominal charge end voltage can double the number of cycles.

Figure 2: Dependence of the cyclical life on the charging level and discharge of a Li-ion cell

The amount of charging currents is an important aspect for determining and influencing the service life. Due to time savings, in practice, a quick charging method is used. The charging current is often a multiple of the standard charging current specified in the data sheet, which leads to a drastic reduction in the number of cycles in a consistent use of the quick charging process due to the higher thermal and mechanical stress on the cells. FRIWO’s measurements show that charging with 1C instead of 0.5C nearly halves the cyclical life.
Cyclical aging therefore depends significantly on the application and battery use. The more accurately the load conditions of the application can be modeled, the more precisely the cyclical aging can be investigated and estimated by means of long-term measurement.

Factor 2: Calendrical aging
With increasing cell age, chemical deterioration processes start which can attack the electrolyte as well as anode and cathode materials. The concomitant loss of capacity is described by the second aging mechanism: the so-called calendrical aging.
Decisive factors for this decay process are the charging state of the cells and the ambient temperature. According to the “RGT rule” (reaction rate temperature rule, also known as van ‘t-Hoff’s rule) the calendrical life is halved at a temperature increase of 10 K.
The following arithmetic example is meant to exemplarily depict a possible estimate of calendrical aging. As a first approximation, a linear approach can be chosen.
A cell manufacturer reports a 90 % recovery for his cell after 1.5 years in a temperature range of -30…25°C. According to the manufacturer, the official end of life reads 60 %. This suggests a theoretical service life in conjunction with calendrical aging if the cell is stored according to the specifications: with 10 % capacity loss per 1.5 years, a total of six years elapse until the final value of 60 % is reached. However, in reality, this theoretical life will be reduced due to the cyclical aging and application, which will ultimately be less than six years.
The specific cyclical aging of a rechargeable battery can be investigated and estimated by FRIWO on the basis of load profiles. Considering the calendrical aging, a realistic service life estimation of the battery pack is thus possible.

Coronavirus: General information on the effects on FRIWO

Entering the factory premises

Our factory premises are currently subject to strict access regulations and increased hygiene measures. The use of the premises is reduced to a necessary minimum.

If it is absolutely necessary to enter the premises for activities, our staff keeps a record of their contacts with each other.

Access regulations

Only our own employees have access to the premises, who

  • have not stayed in a designated risk area
  • do not show flu-like symptoms
  • have had no contact with confirmed or suspected cases of coronavirus infection


In order to prevent further spread of the virus, our team members are mostly in their home offices. Here they can still be reached under the known telephone numbers, by e-mail or via video conference.

Of course, they are still highly motivated to take care of your concerns and projects!


Our production continues at all locations under consistent protective measures for the employees.

These include, for example, increased distance between employees, a time delay at the beginning and end of shift work and the regular disinfection of work surfaces and contact points.

Materials management

In order to ensure smooth material availability, we are in closer coordination with our suppliers than ever before in the current crisis situation.

In addition, there is increased mutual support between our plants in Germany and Vietnam.

Keeping of delivery times

We stand by our word and want to keep our promised delivery times. To achieve this, we rely on measures such as the increased conversion to air freight or the targeted release of alternative components.

As of today, no general negative effects on our delivery dates are discernible.

Despite all security and precautionary measures, we must point out that the far-reaching effects of the pandemic may lead to material bottlenecks and associated delays in delivery in the future. We ask for your understanding in this regard.

It goes without saying that we will inform you as early as possible in the event of such a situation and work with you to solve any challenges that may arise.

Status: 17.03.2020

Download PDF: FRIWO_Covid-19_Information_English

MRSA and its consequences for medical electric devices

Resistance to disinfectants

What means MRSA?

MRSA is the abbreviation of Methicillin-Resistant Staphylococcus Aureus. The antibiotic Methicillin and many further antibiotics are ineffective against these bacteria.
Very often, MRSA is used as a synonym for multi-resistant germs.
For healthy people, such germs are non-hazardous most of the time, they are upon the skin and do not cause an infection. Only if these bacteria get inside the body, an infection can lead to a serious illness.
According to the current state of research, the wrong use of antibiotics supports the origin of multi-resistant germs. Hospitals are very critical sectors, where patients with a weak physical constitution get in contact to a lot of germs, which can easily enter the patients’ body via open wounds.
MRSA germs are transmitted in three ways: human to human, object to human, and animal to human. Most often is the transmission from human to human by direct contact. Touching contaminated surfaces such as door handles, handrails, and objects cause an indirect transmission. Besides, germs stick very well to plastic materials and stainless steel.

Effects on ME devices

In order to confront the spreading of germs, hospitals apply new standards on hygiene. According to relevant professional magazines like „Bundesgesundheitsblatt“ (federal health magazine) and „Empfehlungen des Robert Koch Instituts“ (recommendation of Robert Koch health institute), a periodic surface disinfection of all patient-near areas is demanded.„ (…) A surface disinfection, min. once per day (wiping disinfection) of all areas near patients (bedframe, bedside table, wet area and similar) is necessary, upon demand it should be extended to include further potentially contaminated surfaces (see standards for hospital hygiene and infection preventing, Anlage 6.12 [17] “home cleaning and surface disinfection”). All contact surfaces of devices used by the patient (e.g. buttons of ultrasonic devices, ECG electrodes and leads) have to be wipe-disinfected with disinfectant agents of the DGHM lists directly after use and before being removed from the room. Stethoscopes, thermometers, and similar have to be used patient-related and disinfected immediately after usage. (…)“4  Hence, all surfaces of medical electric devices including accessories which have been touched by the patient or are within his reach should be cleaned.


Disinfectants are agents which lead to a drastic reduction of the number of germs on a surface after application. Usual reduction rates are min. 10-5.
The effect against bacteria (bactericide), viruses (antiviral), fungi (fungicidal), and spores (sporocide) depends on the kind of disinfection agent and its dosage.
The choice of disinfection agents does not only depend on the efficiency against certain germs. It also depends on other factors, e.g. material compatibility and skin sensitivity have to be observed.
There are various chemicals which can be used for disinfection, examples:

  • ethanol
  • isopropyl
  • chlorine
  • iodine
  • amphotensides
  • quaterny ammonium compounds (amines)
  • aldehyde (formaldehyde)
  • peroxide

Very often, manufacturers of disinfectants use mixtures of these substances. Depending on the type of application, they add further substances to create special characteristics, such as balancing the skin’s lipid content after hand disinfection or a special long-term protection.

Disinfectants and plastic housings

The usage of disinfectants on plastic housings or plastic components like leads or sealings has to be critically considered because a number of these disinfectants react with plastic materials and can even destroy them.

Pic. shows an example of a housing, tested by FRIWO: after applying for a short while a high dose of a commonly used aggressive surface disinfectant, cracks were formed which led to destruction of the housing.

As modern plastic materials have to have further features like non-flammability (UL-94V0) and stability, their chemical compatibility differs according to the type of plastic material.

Polycarbonates for example, do react heavily with amines and therefore, they are unsuitable for disinfection with agents containing ammonium compounds like amines. Often, the resistance of plastic housings against the more simple disinfectants like isopropyl/water mixtures is higher than against more complex disinfectants.

A general release of disinfection agents is almost impossible for an ME device manufacturer because the chemical interaction of disinfectants and additives can hardly be assessed. In addition to this, the manufacturers of disinfection agents continually adjust their products.
Actually, ME device manufacturers have only one possibility, i.e. to test single disinfectants and state the results together with test time and dose in their device specification. Due to the fact that this is time and cost consuming, they mostly waive on this for accessory parts and exclude the use of chemical detergents and disinfectants.

FRIWO and disinfecting agents

FRIWO Gerätebau GmbH has been producing power supplies for the medical electric sector for many years. We are your competent partner to advise and help you determine the right power supply solution with required resistance against disinfectants or specify suitable disinfection agents for your power supply.

Please contact us, we look forward to help you: phone +49 (0)2532 / 810 – sales(at)
FRIWO Gerätebau GmbH – Von-Liebig-Str. 11 – 49346 Ostbevern –

1. „Bundeszentrale für gesundheitliche Aufklärung“ (federal center for health information)
2. „Robert Koch-Institut“ (Robert Koch institute), D-13302 Berlin,
3. „Empfehlungen zur Prävention und Kontrolle von Methicillin-resistenten Staphylococcus aureus-Stämmen (MRSA) in medizinischen und pflegerischen Einrichtungen“ (recommendations to prevent and control MRSA in medical and care facilities)
„Bundesgesundheitsblatt“ (federal health magazine) 2014 · 57:696–732 DOI 10.1007/s00103- 014 -1980 –x
© Springer-Verlag Berlin Heidelberg 2014
4. Empfehlung zur Prävention und Kontrolle von Methicillin-resistenten Staphylococcus aureus-Stämmen (MRSA) in Krankenhäusern und anderen medizinischen Einrichtungen (recommendations to prevent and control MRSA in hospitals and other medical facilities)
„Bundesgesundheitsblatt – Gesundheitsforschung – Gesundheitsschutz“ 1999 · 42: 954–958
© Springer-Verlag 1999 (federal health magazine – health research – health protection)
5. „Deutsche Gesellschaft für Hygiene und Mikrobiologie e.V.“ (German association for hygiene and micro biology)

HERC175 awarded as „product of the week“

FRIWO’s new open-frame product line “HERC” is already casting shadows: Although only recently introduced to the market, the first representative of the highly efficient switch mode power supply portfolio has already been ranked “product of the week”by the German medical trade magazine “medtech zwo.

HERC follows in the footsteps of the FOX medical USB line which also made it to the top in the past.

Power supplies for medical equipment in home healthcare environment

The use of medical devices in own homes is always growing. Patients can now perform many treatments outside the hospital. Blood pressure monitors or respirators for Sleep-Disordered Breathing (SBS) are already found in private homes and houses. Electronic devices with communication connections offer new possibilities of outpatient therapy, which is more efficient and cost-effective than a lengthy hospital stay.

Medical-electrical equipment has to meet the special requirements of the home healthcare environment. The IEC60601-1-11 standard defines requirements for the safety and essential performance of medical electrical equipment and systems. In addition the devices need also be compliant to the stronger electromagnetic compatibility requirements according to the IEC 60601-1-2 4th Edition for home healthcare environment.
As home healthcare environment, the norm is understood the house or flat in which a patient is living as well as other places where patients are located, e.g. residential care home for the elderly or vehicles, but no professional health care facilities or facilities for emergency medical services.

The current version of IEC 60601-1-11 was published in April 2016 as “German version EN 60601-1-11: 2015”, a transition period of the previous standard ends 2018-12-31.
The essential performance as well as the safety of medical devices is to be maintained under almost all circumstances, so there are special requirements.

Special electrical Requirements for ME Equipment and their power supplies

The mains voltage in AC power supply networks is usually assumed to be +/- 10% of the nominal voltage, which means that the devices must operate in this range. Because of the bad electrical wiring, in many buildings, ME devices must operate in a range of 85% – 110% of the rated voltage, for life supporting or reanimating devices, are even stricter requirements, which must operate in the range of 80% – 110% of the nominal voltage.

When selecting the power supply, the manufacturer of the ME device must take care, that the power consumption matches to the output data of the power supply also in these case of use.
Furthermore, it should be noted that ME devices which are not permanently connected to the mains:

  • only operated with power supplies of Protection Class II or internally powered
  • are not allowed to use a functional ground
  • Applied parts must be type BF or CF

The background of this requirement lies in the fact that many houses have no functioning grounding. In the case of protection class I devices, a current flows to the earth via the protective conductor in the event of a fault and triggers the residual current circuit breaker (RCD) or a fuse. This may lead to a fatal electric shock if you install a building without or with a bad grounding. Protection class II devices have a double insulation and are safe in the event of this fault.
The functional grounding is used in devices for electromagnetic interference suppression. In the case of a missing grounding, this can lead to malfunctions due to impermissible interference levels. This is also not the case for protective class II devices without a functional grounding.
It is called applied part, if there is an electrically conductive connection between patient and device. In this case, the patient connection must be isolated from the earth and the AC supply network. The current flowing through the patient to the earth when touching the patient connection may not exceed 100μA for type BF and 10μA for CF. Such an applied part can be more easily realized, if the leakage current of the power supply already meets the limit values of for BF or CF.

Special Requirements Ingress Protection

For ME devices used in home healthcare environment, an increased risk of ingress of water is assumed. For this reason, IEC 60601-1-11 specifies the IP protection class IP01, for devices which may be moved during operation or hand-held applications, the protection class IP02 according to IEC 60529 is required. Furthermore, the devices must also be protected against children (protection against the penetration of solid foreign bodies ≥ 5.6 mm) and thus not only meet IP21 or IP22.
External power supplies often meet the protection class IP40 due to the closed plastic housing, but it is a misconception that the enclosed housing automatically protects against ingress of water. Please refer to the manufacturer’s specification and test results and the position of use in the operating instruction.

Special Environment Requirements

If no other information is given in the operating instructions of the ME device, the devices must be operable under the following conditions:

Special Stability Requirements

Devices such as power supplies which are not operable and portable for movement, have to constist, in addition to impact, bump and drop test even a shock test with 15 g (IEC 60068-2-27), and a vibration test according to IEC 60068-2-64.
Shock Test
IEC 600068-2-27:2008
Peak acceleration:     15 g
Duration:                   11ms
Pulse                         Sinus Half wave
Number of shocks:    3 per direction (total 18)
Requirement:            Units fulfill Basic Safety and essential performance

Vibration Test
IEC 600068-2-64:2008
Acceleration amplitude
10Hz – 100Hz: 1,0(m/s²)²/Hz
100Hz – 200Hz -3dB / octave
200Hz – 2kHz 0,5 (m/s²)²/Hz
Duration: 30 min each vertical axis (total 3)
Requirement: Units fulfill Basic Safety and essential performance

Additional Requirements of the IEC60601-1-11

Medical devices for use in a home healthcare environment need to fulfill some requirements for the operating instructions. The instruction must be addressed to the untrained and non-specialist patient as an operator and this must also be considered in the risk analysis.

Special Requirements of the EMC according to the IEC60601-1-2

Medical devices in home healthcare environment must fulfill at least the same, in some point’s even higher, values than in professional Healthcare facility environment. This is caused in the higher pollution by unknown transmission power in different frequency bands (radio, TV, amateur radio, Bluetooth, WLAN, GSM, UMTS, LTE etc.)

The following EM phenomenon’s have higher requirements,

  • Radiated RF EM fields (IEC61000-4-3) 30MHz-2,7 GHz increased immunity level of  10V/m
  • For conducted RF induced by RF fields (IEC 61000-4-6) 150kHz – 80MHz is the 6V immunity level, even valid for amateur radio frequency bands, not only for ISM frequency bands.

Even with the emission the devices must cause less electromagnetic emissions, they must meet the Class B of CISPR 11, this requires a 10 dB lower than the limit value class A, which is required for use in hospitals and clinics.

FRIWO’s new power supply line „FOX“ fulfills the Requirements

FRIWO’s FOX line (FRIWO one click x-change) offers highly efficient power supplies also useable for home healthcare environments. The units meet the most stringent energy effiency standards such as DOE Level VI. Up to now it is not required for medical applications, but it offers a future-proof, which should also be taken into account when selecting the power supply especially from environmental and resource considerations. In addition to the units’ high efficiency, the minimum standby losses are crucial.

Maximum safety is guaranteed by double locking of the housings, minimum leakage currents of ≤ 10 µA and a safety insulation according 2x MOPP. This makes it possible to design a medical device with patient connection, which is considered to be an applied part of class CF
The devices were developed and tested according to the special requirements of IEC60601-1-11 Thanks to interchangeable adapters and a wide range input of 80 to 264 VAC, the units can be used worldwide. In order to meet the requirements of IEC60601-1-11, the optional adapter system with IP42 protection for FOX products must be used. In practical terms, this means that the units can be damp wiped and cleaned – an invaluable advantage in sterile environments.

Since the units are optionally available with white housings, the FOX line perfectly fits in medical applications.
The units already comply with the EMC standard IEC60601-1-2: 2014 (4th Edition) for medical devices, for use both professionally and in a home healthcare environment.
The individual units of the FOX line provide power ratings of 7.5 W (FOX6M), 12 W (FOX12M), 18 W (FOX18M) and 30 W (FOX30M) and cover voltages of 5 to 48 VDC in the standard portfolio. The product line also includes solutions with USB output, in the power rating 11 W (5 V / 2200 mA)  with medical approval according to IEC 60601-1.

In addition to the devices with interchangeable adapter system, FRIWO also offers variants with fixed bottom for country-specific use and the FOX30-DM as desktop version. The standard product in the catalog covers Europe, USA / Japan, UK and Australia. Other country-specific device versions are available on request.
In addition to our direct sales and distribution partners, the units can also be ordered in small and very small quantities on the internet at

Solutions from a single source

As a system supplier, FRIWO offers both chargers and battery packs. In addition to our range of standard solutions, we can design and manufacture custom solutions for stationary and mobile applications. And they all carry the “Made in Germany” label.

FRIWO’s standard portfolio uses premium cells. Our battery packs are equipped with an appropriate protective circuit, which monitors the charging and discharging process, reducing the stress on cells and significantly extending the life of the pack. FRIWO also offers solutions with active cell balancing, to ensure maximum use of capacity. Combined with FRIWO chargers, this results in an optimally balanced overall system.

FRIWO offers extensive development expertise for custom solutions. This allows the company to work closely with customers to create application-specific battery packs using cells from various manufacturers. Along with the optimum configuration of cells, we are capable of implementing complex battery management systems (BMS) including a range of communication systems and parameter queries. Among other things, this makes it possible to indicate the “health” of a battery pack or its charge status, or to implement cell authentication. Along with the capacity to develop and manufacture custom solutions, FRIWO has an internal licensing department, which works closely with the relevant authorities to secure the necessary official approvals.

HERC: Winner in all disciplines

FRIWO is revolutionizing its existing open-frame product portfolio by adding the new product line “HERC”, the product name standing for “High Efficiency and Rapid Customization”. It features two essential characteristics of the compact built-in components: very high efficiency (high efficiency and low standby losses) meets an easy-to-adapt open design for fast customer-specific modifications. The first lines of the new product series include output voltages of 5 – 48 VDC for power classes of 18 W30 W and 175 W.

As to open-frame PS dimensions, standard measures of 3″x2″; 4″x2″ and 5″x3″ for the different power classes have become well-established, and are also met by the HERC series. The very compact design includes, in addition to length and width, the height, which is only 1″- 1.3″ for the HERC line.

With up to 94 % efficiency, the power supplies belong to the top tier. FRIWO also sets new standards for idle power consumption: the DOE VI requirements for external power supplies are exceeded, which is quite unusual for open-frame power supplies. The units can be operated in an ambient temperature range from – 25° C to 70° C. A dual power concept allows the unit to be used both as a convection-cooled and a fan-cooled power supply.

The HERC line meets the medical requirements of IEC60601-1 and can be used worldwide at heights of up to 5000 m. With the protection 2 x MOPP, the insulation of the units is designed for both patient and user safety. The minimum leakage current of < 100 μA (for individual product lines even < 10 μA) allows manufacturers to design medical devices with a patient interface, an applied part of class BF or CF.

In compliance with the new Hazard Base Standard IEC 62368-1, the HERC units also come highly recommended for use in the industry, information technology and audio/video.

In terms of EMC, the new HERC series meets the 4th edition of the IEC 60601-1-2 standard for medical devices, both for professional and domestic use. Furthermore, the requirements for a device of protection class II without functional earth are met, which in turn allows the devices to be used also in domestic areas according to IEC 60601-1-11. With regard to the permissible limit values for harmonic currents of IEC 61000-3-2, units of power ratings > 75 W are equipped with an active PFC.

Further power ratings of the new product line (120 W, 225 W, 350 W, 450 W) are still being engineered and will be launched shortly.

FRIWO now successfully certified according to DIN EN ISO 13485

An additional quality promise to medical technology: After FRIWO has successfully passed the auditing by TÜV Nord in December 2017, the German manufacturer of power supplies has received the official certification according to DIN EN ISO 13485:2012. Backed by this independent authority’s certification, FRIWO’s customers can rely upon that quality management system and development processes within the company do comply with the high regulatory requirements.

“With the certification according to ISO 13485, our teams have reached another milestone we are extremely proud of. By this demanding certification we prove to be a reliable partner for medical technology industry and we strengthen our customers’ confidence in our performance and efficiency”, states Rolf Schwirz, Managing Director for FRIWO, with satisfaction.

DIN EN ISO 13485 defines regulatory requirements for a comprehensive management system of medical product manufacturers. As an internationally accepted standard, this regulation contains guidelines concerning construction and development, production, installation, maintenance, and distribution. This certification imposes high levels for the exact adherence to all process steps. Special attention is paid to consequent and complete documentation and risk management; not only concerning minimization of risks, but also an optimal traceability of products and components.