LD24-xx-xxx Compact, Wide Input Constant Current DC/DC LED Drivers Electrical Specifications Specifications typical @ +25°C, nominal input voltage & rated output current, unless otherwise noted. Specifications subject to change without notice. Key Features: Input Parameter • Constant Current Output Input Voltage Range • Wide 7V to 30V Input Range Max Input Voltage Input Filter • Efficiency to 95% Output • Miniature MiniDIP Case Parameter • 150 mA to 1A Output Output Voltage Range Output Current • Meets EN 60950 Output Current Accuracy • 1.6 MHrs MTBF Output Power • Digital & Analog Dimming! Efficiency Capacitive Load Operating Frequency Ripple & Noise (20 MHz) Models Available Temperature Coefficient with Wire Leads Thermal Impedance (IP67 Rated) Output Short Circuit Environmental Parameter Conditions Typ. 24 Max. 30.0 40.0 Units VDC VDC Min. Typ. 2 VIN = 30V See Model Selection Guide See Model Selection Guide See Model Selection Guide See Model Selection Guide Max. 28 Units VDC 0.5 Sec. Max Internal Capacitor Conditions 47 40 380 See Model Selection Guide ±0.03 ±0.08 Natural Convection +50 Regulated At Rated Output Current Conditions Ambient Case Operating Temperature Range MicroPower Direct 292 Page Street Suite D Stoughton, MA 02072 USA T: (781) 344-8226 F: (781) 344-8481 E: [email protected] W: www.micropowerdirect.com Min. 7.0 Storage Temperature Range Cooling Humidity Lead Temperature (Solder) Remote On/Off Control Parameter DC/DC On DC/DC Off Remote Pin Drive Current Quiescent Input Current (Shutdown Mode) PWM Dimming Parameter Operation Frequency Switch On Time Switch Off Time Output Current Adjustment Analog Dimming Parameter Input Voltage Range Output Current Adjustment Control Voltage Range Limits Drive Current EMC Compliance EMI/RFI Electrostatic Discharge (ESD) RF Field Susceptibility Electrical Fast Transients/Bursts On Mains EMS Immunity Reliability Specifications Parameter MTBF Min. -40 Typ. +25 -40 Free Air Convection RH, Non-condensing 1.5 mm From Case For 10 Sec Conditions Min. VADJ = 1.25V VIN = 30V Conditions Recommended Maximum Min. On Off VADJ = 1.25V Min. 0.0 25 0.30 0.0 Radiated/Conducted Class A Class A Class A Conditions MIL HDBK 217F, 25ºC, Gnd Benign %/ºC ºC/W Max. +85 +105 +125 Units 95 260 % ºC ºC ºC Typ. Max. Units Open or 0.3V < VADJ <1.25V VADJ <0.15V 1 mA 25 µA Typ. 200 200 0.0 Conditions At VADJ Input µF kHz Max. 1.0 100 Typ. Max. 1.25 100 1.25 0.15 1.0 Units kHz nS nS % Units VDC % VDC mA EN 55015 (CISPR22) IEC/EN 61000-4-2, -6, -8 IEC/EN 61000-4-3 IEC/EN 61000-4-4 EN61547 Min. 1.6 Typ. www.micropowerdirect.com Max. Units MHours www.micropowerdirect.com Model Selection Guide Input Model Number LD24-04-150 LD24-07-250 LD24-08-300 LD24-08-350 LD24-14-500 LD24-17-600 LD24-20-700 LD24-24-1000 Output Voltage (VDC) Range 7.0 - 30.0 7.0 - 30.0 7.0 - 30.0 7.0 - 30.0 7.0 - 30.0 7.0 - 30.0 7.0 - 30.0 7.0 - 30.0 Voltage (VDC) Range 2.0 - 28.0 2.0 - 28.0 2.0 - 28.0 2.0 - 28.0 2.0 - 28.0 2.0 - 28.0 2.0 - 28.0 2.0 - 28.0 Notes: 1. A reversed power source could damage the unit. 2. No connection should be made between input ground and the output. 3. These are step-down devices, the maximum output open voltage is equal to the input voltage. Current Max (mA) 150 250 300 350 500 600 700 1,000 Accuracy (%) ±10 ±8 ±6 ±5 ±6 ±7 ±7 ±7 Maximum Power Ripple & Noise (W) (mV P-P, Max) 4.2 7 8 8 14 17 20 24 Efficiency 200 200 200 200 250 250 250 300 Package (%, Max) 95 95 95 95 95 95 95 95 14 -Pin DIP 14 -Pin DIP 14 -Pin DIP 14 -Pin DIP 16 -Pin DIP 16 -Pin DIP 16 -Pin DIP 16 -Pin DIP 4. The VADJ input should be left open if not used. Grounding VADJ will shut the unit down. Connecting VADJ to VIN may damage the unit. 5. Exceeding the specified maximum output power could cause damage to the unit. Typical Connection: DC/DC Input Connection Notes: To comply with EN61000-4-5, a TVS should be installed before the input filter components. A 3.0SMCJ24A or SMCJ24A is recommended. The TVS max clamping voltage (@max peak pulse current VC) must be ⬉⫾40V. Exceeding the maximum input rating could damage the driver. The filter shown (C1, C2 and L1) will help to meet conducted emission requirements. With the addition of the filter, the unit should meet the levels of EN 55015. Typical Connection: AC/DC Input Connection Notes: This is a distributed (or two-stage) AC connection. In this configuration, the AC line in (90 to 264 VAC) is connected to the MPM-30D-15IS, a compact 30W AC/DC power supply. The MPM-30D-15IS is connected across its ±15 VDC outputs to provide a tightly regulated 30 VDC output at 1A. The 30 VDC output powers the LED driver. The two stage approach can simplify the safety approval process (most AC/DC power supplies on the market are approved to EN 60950) and may increase design flexibility. Besides the output power, other specifications to consider when selecting the input AC/DC supply would include input range, safety approvals, PFC rating (which may be needed for various system energy ratings) and operating temperature range. Note: The output current adjustment circuit shown in both connection diagrams is discussed on page 4. 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: [email protected] www.micropowerdirect.com PWM Output Current Control An LED operates at its maximum efficiency when operated at the rated drive current specified by the manufacturer. Operating an LED at lower than its rated forward current not only decreases the system efficiency; but may cause color (or wavelength) shifting. In illumination applications, this could cause visible changes to lighting. A preferred method is using pulse width modulation (PWM). As shown at left, the output current is adjusted by applying a PWM signal to the VADJ input. By varying the signal duty cycle the average output current is adjusted up or down. To avoid visible flicker, the PWM signal should be greater than 100 Hz. For duty cycles (DPWM) between 0 and 1, the output current is derived by the formula: PWM Control Signals INOM = IMAX X DPWM The VADJ input may be driven via an open collector transistor (as shown). The diode and resistor suppress high amplitude negative spikes that may be caused by the drain-source capacitance of the transistor. Negative spikes on the control input of the unit could cause errors in output current or erratic operation. The VADJ input can also be driven by the open drain output of a microcontroller. Again, any high amplitude negative spikes that may be caused by the drainsource capacitance of the FET must be supressed. PWM Dimming Application Get a full explanation of this circuit in “Driving LEDs”. Available free at the MPD website A simple method of achieving digital (or PWM) dimming is by using a 555 timer voltage drops to 1/3 VCC, the discharge pin goes high and C6 begins to charge to apply a series of pulses to the VADJ input, as illustrated above. Again, we are again. The formulas for calculating the frequency and duty cycle are included powering the LED driver with the MPM-30D-15IS AC power supply. in the MPD application note “Driving LEDs”. The 555 operates over a supply voltage range of 4.5 VDC to 18VDC. Here it is connected to the 15 VDC output of the SR7805 switching regulator (also driven by the MPM-20S-24EPB). Care should be taken to minimize ripple at the VCC input. Excess ripple could cause timing errors. The diodes (D1 and D2) allow duty cycles below 50% to be set. Diode D1 bypasses R2 while C6 is charging. Diode D2 is optional (but recommended), essentially blocking R2 during the charge period. Theoretically, this circuit will allow for duty cycles over a range of about 5% to 95%. If manual adjustment is desired, a potentiometer The timer is connected for astable (free run) operation. The frequency is set may be substituted for R2 (with some adjustment of the circuit). by R1, R2 and C6. The timing capacitor (C6) charges through R1 and D2. When The size of C6 is generally not critical, but it should be as low leakage as posit reaches the level of 2/3 VCC, the discharge pin (pin 7) goes low and C6 will sible. In order to avoid excessive current flow through the internal discharge discharge through D1 and R2 to the internal discharge transistor. When the C6 transistor, it is recommended that R1 be at least 5 k⍀. MicroPower Direct • 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: [email protected] The output current of the unit can also be set by adjusting the voltage level on the VADJ input to a value between 0.3V to 1.25V (IOUT will vary from 25% to 100% of rated output current). Care must be taken not to exceed 1.25V on this input, or the driver may be damaged. www.micropowerdirect.com Analog Output Current Control The simple analog circuit at left uses the F2506RW, a 30W, dual 15V output DC/DC converter. Operating from an input line of 12 VDC, the converter sets the input to the LED driver at 30 VDC. The POL regulator, driven off the same input line maintains the control voltage (for the VADJ input) at 5 VDC. The resister network of R1 and R2 can now be used to set the output current level of the LED driver. This level is equal to: VADJ = R2 X V CTRL R1 + R 2 In the second circuit, the input DC/DC has been changed to the F2506RU. The 4:1 input of the converter allows for wider input bus levels (in this case 24 VDC). The POL regulator is also replaced by the shunt regulator (D1). The regulator, connected in parallel with the resistor network, will maintain the voltage across R2 and R3 at 2.5 VDC, insuring that the 1.25 VDC limit on the VADJ pin will not be exceeded. Analog Output Current Control (7 - 30 VDC IN) When using the analog control input, the nominal output current is equal to: INOM = IMAX x VADJ 1.25 The VADJ input should be left open if not used. Grounding VADJ will shut the unit down. Connecting VADJ to directly to +VIN may damage the unit. Mechanical Dimensions - 16 Pin DIP Mechanical Dimensions - 14 Pin DIP Pin Connections - 16 Pin DIP Pin Connections - 14 Pin DIP Pin Function 1 2 3 7 8 -VIN -DC Supply -DC Supply -VIN PWM, On/Off VADJ -LED LED Cathode Conn. -LED LED Cathode Conn. 9 10 15 16 +LED +LED +VIN +VIN LED Anode Conn. LED Anode Conn. +DC Supply +DC Supply Pin Function 1 2 7 -VIN -DC Supply PWM, On/Off VADJ -LED LED Cathode Conn. MicroPower Direct We Power Your Success - For Less! 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • 8 14 +LED +VIN LED Anode Conn. +DC Supply Notes: • All dimensions are typical in inches (mm) • Tolerance x.xx = ±0.02 (±0.50) • Pin 1 is marked by a “dot” or indentation on the top of the unit FAX: (781) 344-8481 • E-Mail: [email protected]