Supertex inc. HV9967DB1 4W LED Driver Demoboard with Accurate Average-Mode Constant Current Control General Description The HV9967DB1 demoboard is a high-brightness LED driver designed to drive 4 LEDs in series at currents up to 350mA from a 20 - 60V DC input. The demoboard uses the Supertex's HV9967 in a buck configuration in a constant offtime mode. The HV9967DB1 LED driver features tight regulation of the LED current within a few milliamps over the entire range of the input voltage (i.e. 20 - 60VDC). The LED current accuracy is almost insensitive to the passive component tolerances, such as the output filter inductance or the timing resistor. PWM dimming can be achieved by applying a pulse-widthmodulated square wave signal between the PWMD and GND pins. Specifications Parameter Specification Input voltage 20 - 60 VDC Output voltage 10 -15VDC (4 x LEDs) Output current 350mA 5% Output current ripple 20% pk-pk (Typical, depending on the type of LED) Switching frequency Variable with constant TOFF = 5s 20% Full load efficiency Typical 80% minimum Output short circuit protection Included, hiccup mode Connection Diagram VLED (+) VLED (-) VIN (+) VIN (-) Connections VDD PWMD GND 1. Connect the LED string between LED+ (Anode of LED string) and LED- (Cathode of LED string). 2. Connect the PWMD terminal to the VDD terminal to enable the LED driver if PWM dimming is not required. Supertex inc. 3. Connect the input DC voltage between the VIN+ and VIN- terminals. 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com HV9967DB1 Circuit Schematic J1 C4 47F 100V 1 2 C3 1.0F 100V + R4 52k3 1% 6 J3 8 R2 1k0 3 2 1 4 7 C1 1.0F 16V J2 U1 HV9967 D1 B1100 RT SW VDD PWMD AGND C2 4.7F 25V RSENSE 2 1 L1 1 330H 2 TP1 R1 0R68 1/4W PGND 3 TP2 Typical Characteristics Output Current vs. Input Voltage (@ VO = 12V) 90% Efficiency vs. Input Voltage (@VO = 12V) 88% 0.360 Efficiency (A) Output Current (A) 0.380 0.340 0.320 86% 84% 82% 0.300 10 20 30 40 50 60 80% 10 70 20 30 Switching Frequency vs. Input Voltage (@VO =12V) 50 60 70 OFF-Time vs. Input Voltage (@ VO = 12V) 6.0 140 Off Time (s) Switching Frequency (kHz) 180 40 Input Voltage (V) Input Voltage (V) 100 5.0 4.0 60 20 10 20 30 40 50 Input Voltage (V) Supertex inc. 60 70 3.0 10 20 30 40 50 Input Voltage (V) 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com 2 60 70 HV9967DB1 Normal Operation: Fig.1-4 shows the waveforms during normal operation at loading of 4 x LED in series at different input. Fig.1: 20V Input Fig.2: 30V Input Fig.3: 40V Input Fig.4: 60V Input Ch1 (Blue) Ch4 (Green) Time Scale Supertex inc. : : : Drain-Source Voltage (10V/div) Output LED Current (50mA/div) 4s/div 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com 3 HV9967DB1 PWM Dimming Operation: PWM dimming operation at 4xLED in series with an external TTL square wave signal is shown in Figs.5 - 7. Fig.5 shows the overall operation of the circuit with PWM dimming input and Fig.6 and 7 show the rise and fall times of the LED current during PWM dimming. Fig.5: PWM Dimming at 24V Ch1 (Blue) Ch4 (Green) Time Scale : : : Fig.6: PWM Dimming at 24V - Rise Time Ch1 (Blue) Ch4 (Green) Time Scale Supertex inc. Drain-Source Voltage (2V/div) Output LED Current (50mA/div) 2ms/div Fig.7: PWM Dimming at 24V - Fall Time : : : Drain-Source Voltage (2V/div) Output LED Current (50mA/div) 2s/div 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com 4 HV9967DB1 Bill of Materials Item# Qty Ref Des Description Package Manufacturer Manufacturer's Part Number 1 1 C1 1F 16V X7R ceramic chip capacitor SMD 0805 Murata GRM21BR71C105KA88L 2 1 C2 4.7F 25V X7R ceramic chip capacitor SMD 1206 Murata GRM31CR71E475KA88L 3 1 C3 1F 100V X7R ceramic chip capacitor SMD 1210 Murata GRM32CR72A105KA88L 4 1 C4 47F 100V 105deg.C electrolytic capacitor SMT Panasonic EEVFK2A470Q 5 1 D1 100V 1A schottky rectifier SMA Diodes Inc B1100-13-F 6 2 J1, J2 2 position 5.08mm pitch vertical header Thru-hole Molex 10-08-5021 7 1 J3 3 position 2.54mm pitch vertical header Thru-hole Molex 22-03-2031 8 1 L1 330H 0.39A 0.45A sat inductor SMT Wurth Elektronik 744 777 233 9 1 R1 0R68 1/4W 1% chip resistor SMD 1206 - - 10 1 R2 1K0 1/8W 1% chip resistor SMD 0805 - - 11 1 R4 52K3 1/8W 1% chip resistor SMD 0805 - - 12 1 U1 Universal LED Driver MSOP-8 Supertex HV9967MG-G Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives an adequate "product liability indemnification insurance agreement." Supertex inc. does not assume responsibility for use of devices described, and limits its liability to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com) Supertex inc. (c)2010 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. 010311 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com 5 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Microchip: HV9967DB1