Benign Environment DC-DC Converters <40 Watt IMR 3 Series 3 Watt DC-DC Converters IMR 3 Series Input to output electric strength test 500 V DC Single or dual output • Input voltage range up to 3:1 • High efficiency up to 73% • Short-circuit proof • No derating • DIL 24 plastic package • Low cost 33 1.3" 12 0.47" 20 0.79" Summary The IMR 3 serie of DC-DC converters have been developed for powering commercial type of electronic circuits, e.g. telephone systems components, industrial controllers and small appliances. They are suitable for applications with standard battery voltages. The IMR 3 converters feature good efficiency and good dynamic response to load changes and at start-up. The IMR 3 modules are short-circuit and no-load proof. Type Survey and Key Data Table 1: Type survey Output Uo nom Io nom [V] [mA] 3.3 1 2 Output power Efficiency 1 hmin Po max [W] [%] 700 2.3 63 Ui min...Ui max 9...18 V DC 2 12 IMR 3-03-2 Input voltage range Ui min...Ui max Ui min...Ui max 18...36 V DC 20...60 V DC Option Ui min...Ui max 36...72 V DC 24 IMR 3-03-2 40 IMR 3-03-2 48 IMR 3-03-2 5 500 2.5 63 12 IMR 3-05-2 24 IMR 3-05-2 40 IMR 3-05-2 48 IMR 3-05-2 12 250 3 65 12 IMR 3-12-2 24 IMR 3-12-2 40 IMR 3-12-2 48 IMR 3-12-2 15 200 3 65 12 IMR 3-15-2 24 IMR 3-15-2 40 IMR 3-15-2 48 IMR 3-15-2 ±5 250 2.5 65 12 IMR 3-0505-2 24 IMR 3-0505-2 40 IMR 3-0505-2 48 IMR 3-0505-2 ±12 125 3 67 12 IMR 3-1212-2 24 IMR 3-1212-2 40 IMR 3-1212-2 48 IMR 3-1212-2 ±15 100 3 67 12 IMR 3-1515-2 24 IMR 3-1515-2 40 IMR 3-1515-2 48 IMR 3-1515-2 -7 Efficiency at Ui nom and Io nom 12 IMR 3 types: Output current Io nom see: Output Data Table of Contents Page Page Summary .......................................................................... 1 Type Survey and Key Data .............................................. 1 Type Key .......................................................................... 2 Functional Description ...................................................... 2 Electrical Input Data ......................................................... 2 Electrical Output Data ...................................................... 3 Electromagnetic Compatibility (EMC) .............................. 4 Immunity to Environmental Conditions ............................. 4 Mechanical Data .............................................................. 5 Safety and Installation Instructions .................................. 5 MELCHER The Power Partners. Edition 4/4.99 1 IMR 3 Series DC-DC Converters <40 Watt Benign Environment Type Key Type Key 24 IMR 3 - 12 12 -2 Nominal input voltage in volt ................................... 12...48 Series .......................................................................... IMR Nominal output power in watt ........................................... 3 Nominal output voltage for output 1 in volt .............. 05...15 Nominal output voltage for output 2 in volt .............. 05...15 Operational ambient temperature range TA –10...50°C .................................................. -2 –25...71°C (option) ..................................... -7 Functional Description 03059 03060 22 Vi+ 22 Vo+ 23 Vi+ 14 Vo+ 14 23 Co Ref. Ci Ci Co Control 9 Co Ref. Vi– Vo– 3 11 2 16 2 Vi– Fig. 1 Single output converter block diagram COM 16 Control Vo– 3 Fig. 2 Dual output converter block diagram Attention: Ci = 4.7 µF/100 V must be added in any application. Co = 10 µF to minimize ripple and noise to <100 mVPP (Capacitors should be of low ESR types). Electrical Input Data General condition: TA = 25°C unless otherwise specified Table 2a: Input data Input 12 IMR 3 Characteristics Conditions Ui Input voltage range U i nom Nominal input voltage TA min...TA max Io = 0...Io nom Ui Input voltage without damage Ii 0 No load input current Ui nom, Io = 0 Ii L Input current limitation response U i rev Reverse input voltage protection MELCHER The Power Partners. min typ 9 24 IMR 3 max min 18 18 22 0 12 0 typ max Unit 36 V DC 24 40 18 12 mA Ui nom, full load 1.25 P i nom 1.25 P i nom W Ui = negative or reverse polarity shunt diode use external fuse Edition 4/4.99 2 shunt diode use external fuse Benign Environment DC-DC Converters <40 Watt IMR 3 Series Table 2b: Input data Input 40 IMR 3 Characteristics Conditions min Ui Input voltage range 20 U i nom Nominal input voltage TA min...TA max Io = 0...Io nom Ui Input voltage without damage Ii 0 No load input current Ui nom, Io = 0 Ii L Input current limitation response U i rev Reverse input voltage protection typ 48 IMR 3 max min 60 36 75 0 typ 36 max Unit 72 V DC 48 0 75 8 8 mA Ui nom, full load 1.25 P i nom 1.25 P i nom W Ui = negative or reverse polarity shunt diode use external fuse shunt diode use external fuse Electrical Output Data General condition: TA = 25°C unless otherwise specified Table 3a: Output data for single output types Output .. IMR 3-03 .. IMR 3-05 Characteristics Conditions min typ max min typ max Uo Output voltage Ui nom, Io nom 3.24 4.90 Io nom Nominal output current: – 12 IMR 3 types – other types Ui min...Ui max (0.2...1) Io nom Output voltage noise: – without Co – with Co Ui nom Io nom (BW = 20 MHz) DUo U Static line regulation U i min...U i max Io nom DUo I Static load regulation U i nom (0.2...1) Io nom aUo Temperature coefficient fs Switching frequency U i nom Io nom uo 3.36 560 700 .. IMR 3-12 .. IMR 3-15 min typ max 5.10 11.76 400 500 min typ max 12.24 14.70 200 250 15.30 150 200 Unit V mA 300 100 300 100 300 100 300 100 mVpp ±1 ±1 ±1 ±1 % ±0.02 %/K ±2 ±2 ±0.02 ±2 ±0.02 50 ±2 ±0.02 50 50 50 kHz Table 3b: Output data for dual output types Output .. IMR 3-0505 Characteristics Conditions min Uo Output voltage Ui nom, Io nom ±4.90 Io nom Nominal output current: – 12 IMR 3 types – other types Ui min...Ui max (0.2...1) Io nom Output voltage noise: – without Co – with Co Ui nom Io nom (BW = 20 MHz) DUo U Static line regulation U i min...U i max, Io nom DUo I Static load regulation U i nom (0.2...1) Io nom aUo Temperature coefficient fs Switching frequency U i nom Io nom uo MELCHER The Power Partners. typ .. IMR 3-1212 max min ±5.10 ±11.76 ±200 ±250 typ .. IMR 3-1515 max min ±12.24 ±14.70 ±100 ±125 typ max Unit ±15.30 V ±80 ±100 mA 300 100 300 100 300 100 mVpp ±1 ±1 ±1 % ±0.02 %/K ±5 ±5 ±0.02 50 ±0.02 50 Edition 4/4.99 3 ±5 50 kHz IMR 3 Series DC-DC Converters <40 Watt Benign Environment Thermal Considerations Connection in Parallel If a converter is operated, the relationship between the ambient temperature TA and the case temperature TC depends heavily on the conditions of operation and integration into a system. The thermal conditions are influenced by input voltage, output current, airflow, temperature of surrounding components and surfaces and the properties of the printed circuit board. The specified maximum ambient temperature TA max is therefore only an indicative value and under practical operating conditions, the ambient temperature TA may be higher or lower than this value. The outputs of several units can be connected in parallel. However, the use of a single unit with a higher power rating is a better choice because of uneven power distribution among the outputs connected in parallel. It is recommended to select converters to be connected in parallel with very small output voltage differences at full load (i.e. <±0.5%). A decoupling diode is not required but recommended. Protection Scheme The IMR series is continuously short circuit protected by means of input power limitation. The unit will not be damaged if started up into a short circuit. After removal of the short circuit, it will resume normal operation. Caution: The case temperature TC measured at the Measuring point of case temperature TC (see: Mechanical Data) may under no circumstances exceed the specified maximum value. The installer must ensure that under all operating conditions TC remains within the limits stated in the table: Temperature specifications. The IMR series is also no-load proof, meaning that the regulation is still effective with no load and the output voltage does not rise. However, due to component tolerances, oscillation could occur and ripple and noise can be outside of specified values. If the converter is used in senitive electronic circuits with no-load conditions, it is recommended to pre-load the outputs with at least 20% of the specified nominal load. Connection in Series The outputs of one or more units can be connected in series. No suppressor diodes are required. Melcher however recommends to protect each individual output with a Zener diode or preferably a suppressor diode, to avoid reverse polarity that may occur if the output voltages do not rise simultaneously. Electromagnetic Compatibility (EMC) 07025 Filter recommendations for compliance with CISPR 22/EN 55022, class B Vi+ Electromagnetic emission requirements according to EN 55022, class B can be easely achieved by adding an external input filter consisting of three additional capacitors and one commom mode ring core choke. C1 C2 L1 Ci Vi– The filter components should be placed as close as possible to the input of the converter. Fig. 3 Input filter arrangement Table 4: Input filter components C1 Input voltage 12, 24, 40, 48 V DC 1 C2 µF 1 µF 1 2.2 100 V 2.2 100 V Type L1 Type Ci Type Siemens B 32522 C1225-K 2.2 mH Siemens B 82722 A2202-N1 4.7 µF 100 V Al-Chip (low ESR) Only valid for input voltages up to 60 V DC. Immunity to Environmental Conditions Table 5: Temperature specifications, valid for air pressure of 800...1200 hPa (800...1200 mbar) Temperature Standard -2 Option -7 Characteristics Conditions min max min max Unit TA Ambient temperature Ui nom –10 50 –25 71 °C TC Case temperature Io = Io nom –10 80 –25 85 TS Storage temperature Non operational –25 85 –40 100 Table 6: MTBF Values at specified case temperature Ground Benign 40°C Ground Fixed 40°C Ground Mobile 50°C MTBF according to MIL-HDBK-217F, N2 3'984'000 h 896'100 h 343'800 h MELCHER The Power Partners. Edition 4/4.99 4 Benign Environment DC-DC Converters <40 Watt IMR 3 Series Mechanical Data Dimensions in mm. Tolerances ±0.3 mm unless otherwise specified. European Projection 09038 min. 33.8 31.8 min. 22.3 20.3 15.24 2.54 1 Measuring point of case temperature TC Fig. 4 Case: DIL 24 Weight: 16 g min. 3 12 mounting space required ø 0.5 Safety and Installation Instructions Table 7: Pin allocation Installation Instruction Installation of the DC-DC converters must strictly follow the national safety regulations in compliance with the enclosure, mounting, creepage, clearance, casualty, markings and segregation requirements of the end-use application. Pin Single output unit Dual output unit 2 Vi– Vi– 3 Vi– Vi– Connection to the system shall be made via a printed circuit board according to: Mechanical Data. 9 n.c. COM 10 n.c. n.c. The units should be connected to a secondary circuit. 11 n.c. Vo– Check for hazardous voltages before altering any connections. 14 Vo+ Vo+ Ensure that a unit failure (e.g. by an internal short-circuit) does not result in a hazardous condition. See also: Safety of operator accessible output circuit. 15 n.c. n.c. 16 Vo– COM 22 Vi+ Vi+ 23 Vi+ Vi+ Input Fuse To prevent excessive current flowing through the input supply line in case of a short-circuit across the converter input an external fuse should be installed in a non earthed input supply line. We recommend a fast acting fuse F2A for 12 IMR 3 types, F1A for 24 IMR 3 types, F0.5A for 40 IMR 3 and 48 IMR 3 types. Table 8: Electric strength test voltages, clearance and creepage distances Characteristic Input to output Unit Electric strength test voltage 1 s 350 Vrms 500 V DC ≈45 pF >1000 MΩ Cleaning Agents Coupling capacitance In order to avoid possible damage, any penetration of cleaning fluids is to be prevented, since the power supplies are not hermetically sealed. Isulation resistance at 500 V DC Protection Degree The protection degree of the DC-DC converters is IP 40. MELCHER The Power Partners. Edition 4/4.99 5 IMR 3 Series DC-DC Converters <40 Watt Benign Environment Safety of operator accessible output circuit Standards and approvals If the output circuit of a DC-DC converter is operator accessible, it shall be an SELV circuit according to IEC/EN 60950 related safety standards The units have been evaluated for: • Building in • Operational insulation input to output • The use in a pollution degree 2 environment • Connecting the input to a secondary circuit which is subject to a maximum transient rating of 500 V. The following table shows some possible installation configurations, compliance with which causes the output circuit of the DC-DC converter to be an SELV circuit according to IEC/EN 60950 up to a configured output voltage (sum of nominal voltages if in series or +/– configuration) of 30 V. However, it is the sole responsibility of the installer to assure the compliance with the relevant and applicable safety regulations. More information is given in: Technical Information: Safety. Isolation The electric strength test is performed as factory test in accordance with IEC/EN 60950 and UL 1950 and should not be repeated in the field. Melcher will not honour any guarantee claims resulting from electric strength field tests. Table 9: Insulation concept leading to an SELV output circuit Conditions Front end Supply voltage Minimum required grade of isolation, to be provided by the AC-DC front end, including mains supplied battery charger Mains Basic ≤250 V AC Double or reinforced DC-DC converter Result Maximum DC output voltage from the front end 1 Minimum required safety status of the front end output circuit Measures to achieve the specified safety status of the output circuit Safety status of the DC-DC converter output circuit ≤60 V Earthed SELV circuit 2 Operational insulation, provided by the DC-DC converter SELV circuit ELV circuit Input fuse 3 output suppressor diodes 4, and earthed output circuit 2 Earthed SELV circuit SELV circuit >60 V Hazardous voltage secondary circuit ≤60 V SELV circuit Operational insulation, provided by the DC-DC converter >60 V TNV-2 circuit Earthed output circuit 2 Double or reinforced insu- Input fuse 3 and output lated unearthed hazardous suppressor diodes 4 voltage secondary circuit 5 1 2 3 4 5 Earthed SELV SELV circuit The front end output voltage should match the specified input voltage range of the DC-DC converter. The earth connection has to be provided by the installer according to the relevant safety standard, e.g. IEC/EN 60950. The installer shall provide an approved fuse (type with the lowest rating suitable for the application) in a non-earthed input conductor directly at the input of the DC-DC converter (see fig.: Schematic safety concept). For UL’s purpose, the fuse needs to be UL-listed. See also Input Fuse. Each suppressor diode should be dimensioned in such a way, that in the case of an insulation fault the diode is able to limit the output voltage to SELV (<60 V) until the input fuse blows (see fig.: Schematic safety concept). Has to be insulated from earth by double or reinforced insulation according to the relevant safety standard, based on the maximum output voltage from the front end. ~ Mains ~ 10004 Fuse AC-DC front end Battery Earth connection + DC-DC converter Suppressor diode SELV – Earth connection Fig. 5 Schematic safety concept. Use fuse, suppressor diode and earth connection as per table: Safety concept leading to an SELV output circuit. MELCHER The Power Partners. Edition 4/4.99 6