Supertex inc. HV9980DB1 3-Channel LED Array Driver IC General Description The HV9980B1 demoboard is an RGB or multi-channel white LED backlight driver designed to drive LEDs for a large-screen TV. The HV9980DB1 can drive three common-anode LED strings from a 100 - 140V input at currents up to 70mA in steady state. It can also drive the LEDs at currents as large as 160mA for short durations to facilitate backlight scanning mode. Each of the three channels can be individually controlled by PWM dimming. The demoboard is also protected from short circuit conditions across any string and recovers automatically once the condition disappears. Specifications Parameter Input voltage (VIN) IC supply voltage (VDD) Output voltage Output current (steady state) Value 100 - 140V 6.0 - 10V 20V (min) < ½ of input voltage (max) 70mA (max) Output current (short durations) 160mA (max) Switching frequency (requires an external 1.8MHz clock signal) 300kHz REF input 0 - 1.0V Output current ripple (typ) Efficiency (@ 120V input and 40V, 50mA output) <5% peak - peak ~90% Open LED protection YES Output short circuit protection YES Connection Diagram 120V 0 - 0.9V + - + + - 8.0V Actual Board Size: 68.8mm x 36.1mm Doc.# DSDB-HV9980DB1 A032913 Supertex inc. www.supertex.com HV9980DB1 Connections Pin Connection VIN Powers the three LED strings, providing the LED string voltage is less than ½ of the input voltage. Connect a high voltage 100 - 140V source at this terminal. VDD Powers the HV9980 control circuit. Connect a 6.0 - 10V source at this terminal. REF Voltage at the REF terminal controls the output current level. The peak inductor current is approximately 1/5th of the REF voltage. CLK Provides a clock input to the HV9980. The switching frequency is 1/6th of the CLK frequency. Connect a 1.8MHz TTL compatible signal at this terminal. These inputs can be used to PWM dim the three channels. Connect these pins to VDD to enable all three PWMD1-3 channels permanently. A TTL compatible, low frequency (<1kHz) square wave can be used to PWM dim each channel individually. GND(s) The two GND terminals are wired together on the board. They form the return path for all the input signals. COM This is the common anode connection for all three LED strings. Ch1-3 These terminals are the cathode connections for the three LED strings. Typical Results Efficiency vs. Input Voltage (@VO = 40V; IO = 50mA) 92 95 Efficiency (%) Efficiency (%) 91 90 89 Efficiency vs. Load Voltage (@VIN = 120V; IO = 50mA) 90 85 80 88 87 90 110 130 75 15 150 Line Regulation of Output Current Output Current (mA) Output Current (mA) 55 53 51 49 130 150 15 25 35 45 Load Voltage (V) Input Voltage (V) Doc.# DSDB-HV9980DB1 A032913 (@VIN = 120V) 57 110 45 Load Regulation of Output Current (@VO = 40V) 49.5 49 90 35 Load Voltage (V) Input Voltage (V) 50 25 2 Supertex inc. www.supertex.com HV9980DB1 Fig.1 shows the drain voltage and LED current waveforms during normal operation. The three channels are phase shifted by 120° with respect to each other. The switching frequency for each channel is 300kHz (1/6th of the CLK frequency). Drain of channel 1 Drain of channel 2 Drain of channel 3 LED current in Channel 1 Fig. 1: Steady State Operation (Time scale: 1.0µs/div) Fig. 2 shows the hiccup mode short circuit protection of the HV9980. The output of channel is shorted by connecting COM to CH1. Channel 1 tries to restart every 200μs. The other two channels work normally and are not affected by the short circuit on one channel. The short circuit timing is started when the voltage at RS reaches 1.15V (about 230mA). Drain of channel 1 Drain of channel 2 LED current in Channel 1 Drain of channel 3 Fig. 2: Operation during Output Short Circuit (Time scale: 50µs/div) Doc.# DSDB-HV9980DB1 A032913 3 Supertex inc. www.supertex.com HV9980DB1 Fig. 3 shows the recovery of Channel 1 from short circuit condition to normal operation. The circuit transitions from a fault condition to normal operation does not cause any overshoots in the LED current. Drain Voltage of Channel 1 LED Current for Channel 1 Fig. 3: Recovery from a short circuit condition (Time scale: 50µs/div) Doc.# DSDB-HV9980DB1 A032913 4 Supertex inc. www.supertex.com HV9980DB1 Fig. 4 shows the PWM dimming performance of the HV9980DB1 for one of the channels. The driver has a 25μs rise time and 50μs fall time. PWM Dimming signal LED Current (a): PWM Dimming Operation (Time scale: 500µs/div) PWM Dimming signal PWM Dimming signal LED Current LED Current (b): PWM Dimming Rise (c): PWM Dimming Fall (Time scale: 50µs/div) (Time scale: 50µs/div) Fig. 4: PWM Dimming performance Doc.# DSDB-HV9980DB1 A032913 5 Supertex inc. www.supertex.com HV9980DB1 Fig. 5 shows the response of the HV9980DB1 to a quickly varying reference voltage, similar to variation found in the backlight-scanning mode. The reference voltage is varied from 250mV to 500mV using a square wave signal (corresponding to an LED current variation from 50mA to 100mA). The LED current transitions quickly between the two levels within 10μs. REF signal LED Current (a): Operation with a REF change (Time scale: 500µs/div) REF signal REF signal LED Current LED Current (b) : Rise Time of LED Current (c) : Fall Time of LED Current (Time scale: 10µs/div) (Time scale: 10µs/div) Fig. 5: REF change response Doc.# DSDB-HV9980DB1 A032913 6 Supertex inc. www.supertex.com Doc.# DSDB-HV9980DB1 A032913 REF VDD GND1 GND VIN 7 0 C4 1.0nF 1k R4 C1 1.0µF 0 C5 1.0nF 1k R5 C2 1.0µF C9 0.22µF 250V C6 1.0nF 1k R6 C3 1.0µF PWMD3 PWMD2 PWMD1 REF3 REF2 REF1 VDD3 VDD2 D1 GND3 CS3 RS3 D3 GND2 CS2 RS2 D2 GND1 CS1 RS1 HV9980 VDD1 CLK POL GND U1 PWMD3 12 9 4 10 7 1 11 8 2 3 6 5 PWMD2 0 PWMD1 CLK 13 14 15 16 20 19 18 17 24 23 22 21 4.99 R3 4.99 R2 4.99 R1 1 1 1 2 3.3mHz L3 3.3mHz L2 3.3mHz L1 2 2 C12 0.1µF 250V C11 0.1µF 250V C10 0.1µF 250V CH3 CH2 CH1 COM HV9980DB1 Circuit Schematic Supertex inc. www.supertex.com D3 BAV20W D2 BAV20W D1 BAV20W HV9980DB1 Bill of Materials Item # Qty RefDes Description Package Mfg Mfg Part Number SMT Keystone Electronics 5016 1 13 PWMD1-3, Ch1-3, REF, VDD, VIN, Compact surface mount test points COM, GND, GND1, CLK 2 3 C1, C2, C3 1.0uF, 16V X7R ceramic chip capacitor SMD0805 TDK Corp C2012X7R1C105K 3 3 C4, C5, C6 1.0nF, 50V X7R ceramic chip capacitor SMD0805 Kemet C0805C102K5RACTU 4 1 C9 Radial Epcos Inc. B32521C3224J 5 3 C10, C11, C12 0.1µF, 200V, X7R ceramic chip capacitor SMD1210 AVX Corp 12102C104KAT2A 6 3 D1, D2, D3 200V, 200mA switching diode SOD-123 Diodes Inc BAV20W 7 3 L1, L2, L3 3.3mH, 225mA sat, 150mA rms inductor Radial Coilcraft RFB0810-332 - - --- Cross Reference (for L1, L2, and L3) Radial Renco USA RL-5480-3-3300 8 3 R1, R2, R3 4.99Ω, 1/8W, 1% chip resistor SMD0805 --- --- 9 3 R4, R5, R6 1.0kΩ, 1/8W, 5% chip resistor SMD0805 --- --- 10 1 U1 Three Channel LED Driver SOIC-24 Supertex HV9980WG-G 0.22µF, 250V metal film capacitor 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-HV9980DB1 A032913 8 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com