link to page 4 link to page 4 Forced Frequency Resonant Flyback controllerPin Configuration and Functionality 1Pin Configuration and Functionality The pin configuration is shown in Figure 2 and the functions are described in Table 1. 1 12 ZCD GND 2 11 MFIO X VCC DP 3 10 GPIO GD0 S 4 CS 9 GD1 210 71 HV 5 8 HV HV 6 7 HV PG-DSO-12-20 Figure 2Pin Configuration of XDPS21071Table 1Pin Definitions and FunctionsSymbolPinTypeFunction ZCD 1 I Zero Crossing Detection ZCD pin is connected to an auxiliary winding for zero crossing detection and positive pin voltage measurement. MFIO 2 I Multi-Functional Input Output MFIO pin is connected to an optocoupler that provides an amplified error signal for the PWM mode operation. GPIO 3 IO Digital General Purpose Input Output GPIO pin provides an UART interface until brown-in. It is switched to weak pull down mode and disabled UART function during normal operation. CS 4 I Current Sense CS pin is connected via a resistor in series to an external shunt resistor and the source of the power MOSFET. HV 5, 6, 7, 8 I High Voltage Input HV pin is connected to the rectified bulk voltage. An internally connected 600 V HV startup-cell is used for initial VCC charge. Furthermore brown-in and brownout detection is provided. GD1 9 I FFR Signal Gate Driver Output GD1 pin provides a gate driver pulse signal to initiate the forced frequency resonant mode operation. GD0 10 O Gate Driver Output Output for directly driving the main power MOSFET. VCC 11 I Positive Voltage Supply IC power supply. GND 12 O Power and Signal Ground Data Sheet 4 Revision 2.0 2019-10-30