VPS8703B

IGBT/SiC gate driver power supply; isolated interface auxiliary power supply; precision instruments, medical instruments; DCS/PLC auxiliary power supply; UPS and photovoltaic inverters; distributed power supply, radio power supply, telecom power supply. VPS8703B is a transformer driver designed specifically for micro-power isolated power supplies with small form factor and low standby power consumption. With only simple input/output filter capacitors, an isolation transformer, and a rectifier circuit, it can realize an isolated power supply with 6~30V input voltage, multiple output voltages, and 1~10W output power. VPS8703B integrates two N-channel power MOSFETs and two P-channel power MOSFETs internally, connected in a bridge configuration. An on-chip oscillator provides a pair of high-precision complementary signals, ensuring highly symmetrical drive for both power MOSFET channels and preventing magnetic flux imbalance during operation. VPS8703B integrates frequency synchronization and multiple protection features. When an external clock signal is applied to the CLK pin, VPS8703B outputs two complementary drive signals at half the external clock frequency. An internal high-symmetry dead-time control circuit ensures no shoot-through occurs under any operating condition. Integrated overcurrent detection protection and over-temperature protection prevent device damage under abnormal conditions such as output short circuit. VPS8703B is a full-bridge topology DCDC isolated switching power supply integrated controller. The bridge drive topology requires fewer transformer windings and reduces cost. It supports 6V~30V applications with strong compatibility. When current is excessive, the power transistor current is clamped to limit it, ensuring the chip operates within its safe operating area while protecting peripheral components from high-current stress. When the CLK pin is left floating (internally pulled high) or connected to GND, the internal switching frequency fSW0 is automatically selected. When CLK is floating, the dead time is fixed; when CLK is connected to GND, the dead time operates in adaptive mode — the power transistor is turned on only after the drain voltage drops, enabling zero-voltage switching to improve efficiency and reduce EMI. CLK can also accept an external synchronization clock signal, in which case the output frequency is half the clock frequency. The EN pin controls chip enable and disable. When EN is pulled high (pulled high internally when floating), the chip operates normally; when EN is pulled low, the chip shuts down, achieving ultra-low standby power consumption.

Applications

• IGBT/SiC gate drive power supply
• Isolated interface auxiliary power supply
• Precision instruments, medical instruments
• DCS/PLC auxiliary power supply
• UPS and photovoltaic inverters
• Distributed power supply, radio power supply, telecom power supply

Key features

• Full-bridge topology
• Optional open-loop LLC drive mode
• High integration, simple peripheral circuitry
• Integrated 30V / 0.25Ω NMOS
• Integrated 30V / 0.60Ω PMOS
• 0.9A current clamp limit
• 6 - 30V input voltage range
• Input surge voltage up to 38V
• Frequency synchronization
• Adaptive dead-time adjustment
• Enable shutdown function
• Integrated soft-start
• Sustained short-circuit protection, over-temperature protection, auto-recovery
• Operating temperature range: -40°C ~ +125°C