VPC2187B

The VPC218XB series is a highly integrated power control IC compatible with multiple topologies (Flyback, Buck, Boost) and output voltage feedback methods (PSR, SSR, resistor divider). It integrates an ultra-wide range startup circuit supporting input voltages from as low as 4V up to 100V. An internal anti-reverse diode prevents current from flowing back from the VDD pin to the VIN pin. The VPC218XB integrates an internal current-sense differential amplifier to significantly improve the signal-to-noise ratio of current sensing, reducing the current-limiting threshold voltage at the CS pin to 156mV. This greatly reduces power dissipation in the current sensing circuit. The design eliminates the need for a current transformer, thereby lowering cost and improving reliability. In SSR mode, the VPC218XB allows the user to enable or disable the analog frequency reduction feature via the FB pin connection. When analog frequency reduction is enabled, the controller operates at a fixed maximum switching frequency under PWM modulation at heavier loads. As the load decreases to a certain level, the controller transitions through stepped analog frequency reduction modes to optimize efficiency across the full load range, while achieving lower ripple voltage and no-load power consumption at light loads. The VPC218XB supports PSR feedback at switching frequencies of several hundred kHz. The built-in output voltage sampling circuit operates in both CCM and DCM modes, with a minimum sampling voltage time window as low as 350nS. The built-in loop compensation circuit with fast dynamic response ensures excellent stability and dynamic performance of the switching power supply. The VPC218XB provides programmable input undervoltage protection with hysteresis, output short-circuit protection, output overvoltage protection, and over-temperature protection, ensuring high reliability of the switching power supply across the full operating range. The VPC218XB is a highly integrated current-mode PWM controller suitable for a wide range of switching power supply topologies including Flyback, Forward, Buck, and Boost. It integrates a high-voltage startup circuit and an anti-reverse diode for a simple external startup circuit. The integrated current differential amplifier improves the SNR of current sensing and enables ultra-low current threshold comparison. Multiple loop feedback modes are supported, and the high-speed PSR sampling circuit enables optocoupler-free isolated switching power supplies operating at frequencies of several hundred kHz. An external programmable soft-start function allows the soft-start time to be configured as needed to reduce startup stress and output overshoot. Built-in slope compensation prevents sub-harmonic oscillation. All protection triggers incorporate debounce filtering to prevent false triggering from noise. Under all fault conditions, unnecessary modules are shut down to minimize power consumption. At very light loads, the device enters a deep frequency reduction mode to lower no-load power consumption while keeping ripple within acceptable limits and preventing audible noise. Comprehensive protection features are provided for the switching power supply: the UVP pin enables user-configurable input undervoltage protection threshold and hysteresis; the VDD pin implements output overvoltage protection; the COM pin provides output overload and open-loop protection; the CS pin implements transformer or output short-circuit protection.

Applications

• Discontinuous (DCM)/Continuous (CCM) mode flyback converter
• Industrial power conversion
• BMS auxiliary power supply
• PoE power supply
• Isolated communication power supply

Key features

• Ultra-wide input voltage range 4V~100V startup circuit
• Compatible with Flyback, Boost, and Buck topologies
• Current limit threshold voltage: 156mV or 500mV selectable
• Single-resistor programmable oscillator frequency
• Light-load analog frequency reduction for optimized efficiency curve; programmable disable of analog frequency reduction; no-load burst mode for low no-load power consumption; enable shutdown current as low as 0.1μA
• Cycle-by-cycle current limiting protection, short-circuit protection, and over-temperature protection
• Leading-edge blanking of current sense signal
• Built-in slope compensation circuit
• Precisely configurable input UVLO and hysteresis
• Optional internal or external soft-start
• Built-in PSR loop control in CCM/DCM mode
• Direct optocoupler interface
• MSOP10 ultra-compact package