A 6W Ballast Application with the P50 Prepared by: Thierry Sutto This document describes how the P50 driver can be implemented in a ballast application. The scope of this application note is to highlight the P50 driver and not to explain or detailed how to build electronic ballast. The P50 is a high voltage power MOSFET driver providing two outputs for direct drive of N-channel power MOSFETs arranged in a half-bridge configuration with only one input. It uses the bootstrap technique to insure a proper drive of the High-side power switch. The driver works with one input to accommodate half-bridge topology with a fixed dead time of 50 ns. Demo Board Specification Input range : 85 Vac - 5 Vac OR 8 Vac - 65 Vac Ballast Output Power : 6 W (type PL-L 6W) Pre-Heating Current : 95 ma Pre-Heating Time : second Nominal Current : ma NOTE: BEFORE PLUGGING IN THE DEMO BOARD, MAKE SURE THE JUMPER IS ON THE CORRECT POSITION: IF J IS USED, THEN Vin MUST BE LOWER THAN 5 Vac. Detailed Operation The lamp ballast is powered via a half bridge configuration. The power MOSFETs are driven with the P50 driver. The driver is supplied by the V CC rail, and the high side driver is supplied by the bootstrap diode: when the low side power MOSFET (Q) is switched ON, the BRIDGE pin is pulled down to the ground, thus the capacitor connected between BRIDGE pin and VBOOT pin is refuelled via the diode D and the resistor R5 connected to V CC. When Q is switched OFF the bootstrap capacitor C6 supplies the high side driver with a voltage equal to V CC level minus the D forward voltage diode. Given the P50 architecture, the driver copies the input signal to the high side driver, then it generates a fixed dead time (50 ns) before toggling the low side driver when the input pin level changes. Figure. Dead Time Between the High and Low-Side Driver Semiconductor Components Industries, LLC, 007 November, 007 - Rev. 0 Publication Order Number: AND8/D
IN_HI DRV_HI IN_LO DRV_LO Time ( ms/div) Figure. Input Output Timing Diagram Tube Voltage (00 V /div) Tube current (0.5 V /div) Tube Power (50 W/div) Tube average power = W Figure. Tube Signals
Figure. Demo Board Schematic R C C R6 68k R 7k R 7k R0 k R5 k R OR R TRIG CVOLT DIS THR Q VCC 5 6 7 8 C U TLC555C D 5V.W VCC IN SD C7 00 F C 0 F C 7 F 00V C 7 F 00V F T500mA CON J C0 00pF C6 R 8k W R 8k W R k VBOOT DRV_HI Bridge DRV_IO U P50 C 7 F C5 00nF R5 0R D N96 C6 00nF R6 0R R8 0k PT Q IRF80LC Q IRF80LC C5 6.8nF R9 0k R7 0R R 90k D6 N96 C 0pF/00V D5 N96 8 7 6 5 L.mH B BALLAST kv C8 0nF 00V C7 0nF 00V
Figure 5. PCB Printout: Top and Bottom View
BILL OF MATERIAL Part Type Designator Manufacturer Description Connector B, J - Connector 7uF/00V C, C Panasonic M Series 0pF C0 Generic Capacitor 0nF C Generic Capacitor C, C - Capacitor 0pF /00V C Generic Capacitor 6.8nF/kV C5 Generic Capacitor C6 - Capacitor 00uF C7 Generic Capacitor 0uF C Generic Capacitor.7uF/50V C Generic Capacitor 00nF C5 Generic Capacitor 00nF C6 Generic Capacitor 0nF/00V C7, C8 Generic Capacitor 0pF C9 Generic Capacitor BZX85C5V D Generic 5V Zener diode N96 D, D5, D6 ON Semiconductor Fast Recovery rectifier BZX85C5V D Generic 5V Zener diode T500mA F Generic Fuse US-jumper J - Jumper for US main supply only.mh L VOGT VOGT 5-0 DF06M PT - 600V Diode Bridge IRF80LC Q, Q IRF Low Charge N-Channel MOSFET BC57B Q Generic NPN transistor k R Generic Resistor k R0 Generic Resistor 7k R Generic Resistor 7k R Generic Resistor 5k R Generic Resistor 90k R Generic Resistor k R5 Generic Resistor 68k R6 Generic Resistor R - Resistor 8k/W R, R Generic Resistor W power type 0R R5, R6, R7 Generic Resistor 0k R8, R9 Generic Resistor TLC555C U Texas Instrument CMOS 555 timer P50 U ON Semiconductor P50 5
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