Supertex inc. HV9911DB4 High Brightness SEPIC LED Driver Demoboard with High Dimming Ratio and Excellent Current Regulation General Description The HV9911DB4 is an LED driver dempboard capable of driving one to six three-watt LEDs in series from an input of 9.0 - 16VDC. The demoboard uses Supertex’s HV9911 in a SEPIC topology to drive LED string voltages higher or lower than the input voltage. The converter has a very good initial regulation (+/-5%), and excellent line and load regulation over the entire input and output voltage range (<+/-1%). The full load efficiency of the converter is typically greater than 85%. The HV9911DB4 is also protected against open LED and output short circuit conditions. It is protected against over load conditions by limiting the input current. It has an excellent PWM dimming response. The switching frequency of the HV9911DB4 can be synchronized to other HV9911 boards or to an external 350kHz clock by connecting the clock to the SYNC pin of the HV9911DB4. Specifications Parameter Value Input voltage (steady state): Output LED string voltage: Output current: 9.0 - 16VDC 3V min - 24V max 700mA +/-5% Output current ripple: 5% typical Switching frequency: 350kHz Full load efficiency: 87% (at 13V input) Open LED protection: Shuts down at 30V Output short circuit protection: Dimensions Included 56.0mm x 38.2mm Board Layout and Connection Diagram VIN J1 J2 J3 Actual Size: 56.0mm x 38.2mm Connections: Input - The input is connected between the terminals of connector J1 as shown in the connection diagram. Output - The output is connected between the terminals of connector J2 as shown. Enable/PWM Dimming - To enable the board, short pins PWMD and VDD of connector J3 as shown. To use the PWM dimming feature of the board, connect an external push-pull square wave source between terminal PWMD and GND of connector J3 as shown by the dotted lines. Doc.# DSDB-HV9911DB4 A032713 SYNC: To synchronize two or more boards, connect the SYNC pins of all the boards. To synchronize the HV9911DB4 to an external 350kHz clock, connect the clock between SYNC and GND pins of terminal J3. Note: During PWM dimming, VDD of connector J3 should be left open. Also, the PWM signal must have the proper polarity with the positive connected to PWMD of J3. Note that GND of J3 is internally connected to the return path of the input voltage. Supertex inc. www.supertex.com HV9911DB4 Demoboard Testing: Fig.1 Efficiency vs. Output Voltage Normal Operation: Connect the input source and the output LEDs as shown in the connection diagram and enable the board. The LEDs will glow with a steady intensity. Connecting an ammeter in series with the LEDs will allow measurement of the LED current. The current will be 700mA +/- 5%. Efficiency (%) Current Regulation: With the input power to the converter disconnected, change the input voltage or the LED string voltage within the specifications mentioned. The current output of the HV9911DB4 will remain very steady over the entire line range. 85 80 75 70 65 3 8 13 18 23 Output Voltage (V) Fig.2 Efficiency vs. Input Voltage Full Load Efficiency vs. Input Voltage 88 Efficiency (%) With the supply turned off, change the LED string voltage within the specified limits and turn the power supply back on. The current will still be regulated at around 700mA. Open LED test: Connect a voltmeter across the output terminals of the HV9911DB4. Start the demoboard normally and once the LED current reaches a steady state, unplug one end of the LED string from the demoboard. The output voltage will rise to about 30V and the HV9911DB4 will shut down. To restart the converter, disconnect and reconnect the input voltage (recycle the power to the board). 87 86 85 84 83 82 9 11 15 13 Input Voltage (V) 2. Current Regulation: Fig.3 and Fig.4 show the output current regulation vs. load voltage and input voltage respectively. The total current regulation (line and load combined) is less than 1%. Short Circuit Test: When the HV9911DB4 is operating in a steady state, connect a jumper across the terminals of the LED string. Notice that the output current will immediately go to zero and the converter will shut down. To restart the HV9911DB4, recycle the input power to the demoboard. Output Current (A) Fig.3 Output Current vs. Output Voltage PWM Dimming: With the input voltage to the board disconnected, apply a TTL-compatible, push-pull square wave signal between PWMD and GND terminals of connector J3 as shown in the connection diagram. Turn the input voltage back on and adjust the duty cycle and/or frequency of the PWM dimming signal. The output current will track the PWM dimming signal. Note that although the converter operates perfectly well at 1kHz PWM dimming frequency, the best PWM dimming ratio can be obtained at lower frequencies, like 100Hz or 200Hz. Load Regulation (VIN = 13.5V) 0.710 0.705 0.700 0.695 0.690 3 8 13 18 23 Output Voltage (V) Output Current (A) Fig.4 Output Current vs. Input Voltage Typical Results 1. Efficiency: The efficiency of the converter at various LED string voltages are shown in Fig.1 (measured at the nominal input voltage of 24V). Fig.2 shows the full load efficiency of the converter at varying input voltages. The minimum efficiency of 68% for the converter occurs at minimum load voltage. Doc.# DSDB-HV9911DB4 A032713 Efficiency vs. Load Voltage (VIN = 13.5V) 90 Line Regulation (VO = 24V) 0.710 0.705 0.700 0.695 0.690 9 11 15 13 Input Voltage (V) 2 Supertex inc. www.supertex.com HV9911DB4 6. PWM Dimming: Typical PWM dimming response is shown in Fig.8. Fig.9a shows the rise and Fig.9b shows the fall of the LED current on an expanded time scale. 3. Normal Operation: The drain voltage of the switching FET and the output current are shown in Fig.5. It can be seen that the converter is switching at 350kHz, and the output current ripple is about 16% (peak to peak). Fig.8: Typical PWM Dimming Waveforms Fig.5. Switching waveforms for the HV9911DB4 PWM Dimming Input Output Current Drain voltage LED Current Fig.9a. Rise Time (10µs/div) 4. Open LED Protection: Open LED protection for the circuit is set at 30V. The waveforms in Fig.6 show the output voltage, drain voltage, and output current during an open LED condition. The time taken for the over voltage protection to shut the IC down will depend on the size of the output capacitor. PWM Dimming Signal Fig.6. Open LED Protection LED Current Output Voltage LED Current Fig.9b. Fall Time (10µs/div) Drain Voltage of Q1 PWM Dimming Signal 5. Output Short Circuit Protection: Fig.7 shows the waveforms for output short circuit condition. The disconnect FET is turned off in about 300ns. The rise in the output current will depend on the output voltage and the energy stored in the output capacitor. Doc.# DSDB-HV9911DB4 A032713 LED Current 3 Supertex inc. www.supertex.com HV9911DB4 7. Input Audio Susceptibility: Fig.10 shows the response of the converter for a step change in the input voltage from 10 to 16V. The current overshoots by 30% and comes back into regulation in 7ms. Fig. 10. Response of the HV9911DB4 to an input voltage change (Time Scale: 1ms/div) 8. Input Current Ripple: Fig.10 shows the input current ripple of the converter at full load and 13.5V input. The ripple current is about 4% (peak to peak). Input Voltage LED Current Silk Screen Doc.# DSDB-HV9911DB4 A032713 4 Supertex inc. www.supertex.com Doc.# DSDB-HV9911DB4 A032713 5 REF 19.1k R12 REF C8 open 8.66k R9 open R7 6.81k C7 0.1μF 16V R13 C6 0.1μF 16V C1 2.2μF 25V open R4 J3B 17.4k R8 Io_SNS J3A C2 2.2μF 25V VDD J3D J3C PWM CLIM U1 SC RT R11 36k GND OVP FAULT CS GATE VIN HV9911 COMP FDBK IREF REF SYNC C5 1.0μF 16V 1 R5 2 499Ω 261k R2 33μH L1 R6 0.1Ω 1W Q1 FDS3692 C11 1.0μF 50V C10 1.0μF 50V C3 1.0μF 50V 2 Io_SNS L2 100μH 1 C4 2.2μF 50V D1 SK38-TP C12 470pF 50V C9 2.2μF 50V 1k R14 D2 1N4148 J2B C13 1.0nF 50V J2A R10 0.47Ω 0.5W Q2 ZXMN6A11G 2 R3 2.43k R1 56.2k 1 Circuit Schematic: REF 1 J1A 2 J1B HV9911DB4 Supertex inc. www.supertex.com HV9911DB4 Bill of Materials Manufacturer Manufacturer’s Part Number TDK Corp C3225X7R1E225K Kemet C1210C105K5RACTU 2.2μF, 50V X7R ceramic chip capacitor SMD1210 TDK Corp C3225X7R1H225K C5 1.0μF, 16V X7R ceramic chip capacitor SMD0805 TDK Corp C2012X7R1C105K C6, C7 0.1μF, 16V X7R ceramic chip capacitor SMD0805 Murata GRM219R71C104KA01D - - - SMD0805 Kemet C0805C471K5RACTU C13 1.0nF, 50V X7R ceramic chip capacitor SMD0805 Kemet C0805C102K5RACTU 1 D1 80V, 3A schottky diode SMC Micro Commercial SK38-TP 10 2 J1, J2 Side Entry 2-pin male header Thru-Hole JST Sales S2B-EH 11 1 J3 Side Entry 4-pin male header Thru-Hole JST Sales S4B-EH 12 1 L1 33μH, 3A rms, 6A SAT inductor SMT 13 1 L2 100μH, 0.86A rms, 1.0A SAT inductor SMT 14 1 Q1 100V, 4.55A N-Channel MOSFET SO-8 Fairchild FDS3692 15 1 Q2 60V, 2.7A N-Channel MOSFET SOT-89 Zetex, Inc. ZXMN6A11G 16 1 R1 56.2kΩ, 1%, 1/4W chip resistor SMD1206 - - 17 1 R2 261kΩ, 1%, 1/8W chip resistor SMD0805 - - 18 1 R3 2.43kΩ, 1%, 1/8W chip resistor SMD0805 - - 19 1 R5 499Ω, 1%, 1/8W chip resistor SMD0805 - - 20 1 R6 0.1Ω, 5%, 1W chip resistor SMD2512 - -- 21 1 R8 17.4kΩ, 1%, 1/8W chip resistor SMD0805 - - 22 1 R9 8.66kΩ, 1%, 1/8W chip resistor SMD0805 - - 23 1 R10 0.47Ω, 1%, 1/2W chip resistor SMD2010 - - 24 1 R11 36kΩ, 1%, 1/8W chip resistor SMD0805 - - 25 1 R12 19.1kΩ, 1%, 1/8W chip resistor SMD0805 - - 26 1 R13 6.81kΩ, 1%, 1/8W chip resistor SMD0805 - - 27 1 R14 1.0kΩ, 1%, 1/4W chip resistor SMD1206 - - 28 1 U1 Switchmode LED Driver SO-16 Supertex HV9911NG-G Item Qty Ref Des Description 1 2 2 3 3 2 C4, C9 4 1 5 1 6 3 7 1 C12 470pF, 50V, X7R ceramic chip capacitor 8 1 9 C1, C2 Package 2.2μF, 25V X7R ceramic chip capacitor SMD1210 C3, C10, 1.0μF, 50V X7R ceramic chip capacitor SMD1210 C11 R4, R7, C8 open Cooper Electronics Cooper Electronics DR127-330 DR74-101 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. ©2013 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. Doc.# DSDB-HV9911DB4 A032713 6 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com