VPSC VPS8505

VPS8505 is a push-pull transformer driver 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 peripheral components, it achieves isolated power conversion with 3.3V or 5V input, 3.3V~24V output, and 1~3W output power.

The VPS8505 integrates 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. It features enable and frequency synchronization functions, along with an internal high-precision dead-time control circuit that prevents shoot-through under all operating conditions.

VPS8505 is a DCDC isolated switching power supply integrated controller for push-pull topology. The on-resistance of the integrated power transistors is as low as 0.1Ω, supporting applications in the 2.3V~6V range at various power levels. When current becomes excessive, clamping limits the power transistor current, keeping the chip within its safe operating area while protecting peripheral components from high-current stress.

The CLK pin provides frequency synchronization, enabling coordinated operation under an external clock. To ensure drive symmetry, the internal circuitry divides the external clock frequency — meaning the frequency of VD1 and VD2 is half that of the CLK signal. A dead-band time t_BBM is inserted between the two drive signals to prevent shoot-through, reduce the drain-source voltage at turn-on, and minimize switching losses.

The EN pin controls chip enable and disable. When EN is pulled high, the chip operates normally; when EN is pulled low, the chip halts operation, achieving ultra-low standby power consumption.

• Push-pull topology
• High integration, minimal external components
• Built-in 24V / 0.1Ω LDMOS 1.7A current clamp limiting
• 2.3 - 6V input voltage range
• Frequency synchronization
• Enable shutdown function
• Sustained short-circuit protection, over-temperature protection, auto-recovery
• Operating temperature range: -40°C ~ +125°C

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• Process control
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