SNVSCE8 July 2024 LM5190-Q1
ADVANCE INFORMATION
The LM5190-Q1 contains an internal high-voltage VCC bias regulator that provides the bias supply for the PWM controller and the gate drivers for the external MOSFETs. The input voltage pin (VIN) can be connected directly to an input voltage source up to 80V. However, when the input voltage is below the VCC setpoint level, the VCC voltage tracks VIN minus a small voltage drop.
The VCC regulator output current limit is 135mA (minimum). At power up, the controller sources current into the capacitor connected at the VCC pin. When the VCC voltage exceeds 4.8V and the EN pin is connected to a voltage greater than 1V, the soft-start sequence begins. The output remains active unless the VCC voltage falls below the VCC UVLO falling threshold of 4.5V (typical) or EN is switched to a low state. Connect a ceramic capacitor from VCC to PGND. The recommended range of the VCC capacitor is from 2.2µF to 10µF.
The VCC regulator is a dual-input regulator which uses BIAS pin as the other input in addition to the VIN pin. A lower voltage supply such as the buck output (VOUT) or other applicable system rails can be tied to BIAS to reduce the power dissipation of the internal VCC regulator. The VCC regulator switches over to use BIAS voltage as the input when rising across 9V (typical). The switchover voltage hysteresis is 400mV. When using BIAS as the supply, VIN voltage must be greater than VCC voltage during all conditions to avoid damage to the controller. Tie BIAS to PGND if unused. The operational maximum voltage of BIAS is 28V.