Supertex inc. HV9861ADB2

Transcription

1 HV986A LED Driver Demoboard Boost Assisted, Valley Fill, 0VAC Input, 7W Output, 50mA, 0V, Power Factor ~ 9% General Description Certain target markets for LED lighting require a power factor of at least 90%. A power factor over 90% can be attained using valley fill power factor correction with the addition of a small boost converter. HV986ADB The boost converter lowers line current distortion by adding line current draw in the valley and lowering the peak amplitude of the valley fill capacitor recharging current. Circuit add-ons with boost sec on without boost sec on PF 9.6 % PF 90.8 % Basic valley fill circuit operation A valley fill power factor correction circuit operates in two distinctly different modes. During a first period, here referred to as the valley and coinciding with line voltage being lower than half the peak line voltage, the load is exclusively powered from two energy storage capacitors. Consequently, in the valley the line current is equal to zero. The valley, being characterized by a line voltage less than half the peak line voltage, extends 0 on either side of the line voltage zero crossing. During a second period, coinciding with the line voltage being higher than half the peak voltage, the load is exclusively powered from the line and not from the valley fill capacitors. Consequently, the line current is not zero. Furthermore, an additional line current is drawn near the peak of the line voltage for recharge of the valley fill capacitors. The two line current components can clearly be identified in the oscillogram of the line current. Boost converter operation The boost converter adds current draw in the valley, thereby lowering distortion and raising power factor. The boost converter switch, a bipolar transistor in common base configuration, is driven indirectly by the current flow in the valley capacitors. In the valley, current is extracted from the valley capacitors during ON time of the main switch, each capacitor contributing half of the load current. The capacitor current in one of the capacitors develops a voltage of about.v across two diodes in series. This voltage provides a forward bias for the base emitter circuit of the boost transistor. Current develops in the boost inductor, which subsequently flows in to the valley capacitors during OFF time. The boost converter develops a line current with an amplitude which is line voltage dependent. When line voltage is particularly small the boost converter operates in discontinuous mode (DCM) and when the line voltage approaches half the peak voltage the converter operates in continuous conduction mode (CCM). The line current amplitude increases nonlinearly with line voltage in either conduction mode. The boost converter action results in delivery of power to the valley capacitors thereby lowering the amplitude of the capacitor recharging current during the second period.

2 Specifications Parameter Value Input voltage 5 Output voltage 0V DC, ±0% Output current 50 ma DC, ±5% Output power 7W Power factor ~9.6% Total harmonic distortion ~5% EMI limits CISPR 5 Connection Diagram HV986ADB Parameter Value Efficiency ~% Output current ripple (at F SW ) % PP (See note) Output open circuit protection Yes Output short circuit protection Yes Switching frequency 50kHz khz Dimensions 5mm x mm x 0mm Note: Output current ripple can be reduced in straightforward manner by increasing inductor L. Alternatively, capacitor C can be increased. 0 0V DC Connections Connect the mains voltage at the input terminals and connect the LED load at the output terminals as shown. Warning: The mains voltage circuit does not contain galvanic isolation. Do not ground any part of the circuit directly to protective ground by means of test equipment connections. Circuit Schematic D RM007 AN0 RED TP R6 k C n L.5m D + C 0µ C n D C 0n CAT BLU TP TP AC AC TP AC AC F A MOV S07K0 L.5m L.5m R7 k C5 n BR MS R Q STX66 D7 D9 D DN BAV99 R D5 RM007 + C6 0µ D6 L m 5 PWMD VIN GATE HV986A M MN 7 LD CS VDD RT GND C7 n 6 8 R5 k R R.

3 EMI Signature HV986ADB dbμv 0 If BW 9.0kHz 0k k M 0M Hz Notes: PCB suspended approximately inches above reference plane. Peak detector in peak hold mode for 0 min. THD vs. Line Voltage PF vs. Line Voltage 90 % 0 % Efficiency vs. Line Voltage 500 Output Current vs. Line Voltage % ma

4 Line Voltage and Line Current at Nominal Line and Load HV986ADB Line Current and Output Current at Nominal Line and Load

5 HV986ADB (top view) HV986ADB HV986ADB (bottom view) Actual Dimensions: 0mm x 8mm Silk Screen 5

6 HV986ADB Bill of Materials Qty Ref Description Mfr Part Number BR Bridge rectifier 500mA 0VRRM SMD Diotec MS R Resistor thick film /8W % SMD 06 Ω Yageo RC06FR-07RL R Resistor thick film /8W % SMD 05 Ω Yageo RC05FR-07RL R Resistor thick film /8W % SMD 05 Ω Yageo RC05FR-07RL R Resistor thick film /8W % SMD 05.Ω Yageo RC05FR-07RL R5 Resistor thick film /8W % SMD 05 kω Yageo RC05FR-07KL R6, R7 Resistor thick film /8W % SMD 06 kω Yageo RC06FR-07KL C7 Cap ceramic X7R 0% 50V DC SMD 05 nf Yageo CC05KRX7R9BB0 C Cap poly metalized 0% 5C VAC 50VDC 0mm 0nF Epcos B5CK C, C5 Cap poly metalized 5% 5C VAC 50VDC 7.5mm nf Epcos B50CJ C Cap poly metalized 0% 5C VAC 50VDC 7.5mm nf Epcos B50C0K C, C6 Cap electrolytic 05C khr 0% VDC THD 8x9 0µF Rubycon LLE0MEFC8X9 D, D, D, D6 Diode ultrafast A 0V 5ns SMD SOD-H Comchip CS-HF D7 Diode 75V ns SMD SOD- 00mA 00mW Fairchild MMSD9 D, D5 Diode standard A kv SMD SOD-F Comchip CGRM007-G DN Diode network BAV99 00mA 75V ns SMD SOT-- Diodes Inc BAV99-7-F IC IC power management LED driver HV986A SMD SOIC-8 Supertex HV986ALG-G Q Transistor NPN.8W 500V.5A THD TO-9AP STX66 ST Micro STX66-AP M MOSFET N-channel 0V A 8.5R THD IPak STDNK ST Micro STDNK- L Inductor THD 5mmLS 8xmm mh 50mA Abracon AIUR-0H-0K L, L, L Inductor THD 6mm dia.5mh 8.0Ω Wuerth 7765 MOV Varistor MOV THD disc 7mm VDC 0VAC.kA 9.5J Epcos S07K0 F Fuse 00VAC slow TR5 Series 8 A LittelFuse J, J, J, J Buswire AWG Any TP, TP Testpoint PCB compact orange Keystone 50 TP Testpoint PCB compact red Keystone 500 TP Testpoint PCB compact blue Keystone 57 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. 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 (website: http//) 0 All rights reserved. Unauthorized use or reproduction is prohibited. 6 5 Bordeaux Drive, Sunnyvale, CA 9089 Tel: