VPS8504C

VPS8504B\C are two push-pull transformer drivers specifically designed for compact, low standby power micro-power isolated supplies. With only simple input/output filter capacitors, an isolation transformer, and a rectifier circuit as external components, they can realize isolated power supplies with 3.3V or 5V input, 3.3V~24V output, and 1~3W output power. They integrate an internal oscillator that provides a pair of high-precision complementary signals to drive two N-channel MOSFETs. The chip is designed with a symmetrical architecture to ensure a high degree of symmetry between the two power MOSFETs, preventing flux imbalance during operation. VPS8504B features an enable pin EN, and two different operating frequencies can be selected by leaving the CLK pin floating or connecting it to ground. An internal high-precision dead-time control circuit ensures no shoot-through occurs under any operating condition. VPS8504C uses a SOT23-5 package and does not expose the EN function. VPS8504B\C is a DCDC isolated switching power supply integrated controller suitable for push-pull topology, with an internal power transistor on-resistance as low as 0.1Ω, supporting applications across a supply range of 2.8V~6V at various power levels. When the current is excessive, a clamp limits the power transistor current, ensuring the chip itself operates within the safe operating area while protecting peripheral components from high-current stress. Two different operating frequencies can be selected by leaving the CLK pin floating or connecting it to ground. A dead time t_BBM is designed between the two drive signals to prevent shoot-through, reduce the drain-source voltage at power transistor turn-on, and minimize switching losses. The chip can be turned on or off via the EN pin. When EN is pulled high (floating, it is pulled high internally by default), the chip operates normally; when EN is pulled low, the chip stops operating, achieving ultra-low standby power consumption.

Applications

• Low-power isolated power supply for CAN\RS-485\RS-232\SPI\I²C
• Process control
• Precision instruments\Medical instruments
• Distributed power\Radio power\Telecom power low-noise isolated USB power supply
• Low-noise filament power supply IGBT gate drive power supply

Key features

• Push-pull topology
• High integration, minimal external components
• Built-in 24V / 0.1Ω LDMOS with 1.7A current clamp limit
• 2.8 - 6V input voltage range
• Two selectable switching frequencies
• Enable shutdown function
• Continuous short-circuit protection, over-temperature protection, auto-recovery
• Operating temperature range: -40°C ~ +125°C