JAJSUV0 June 2024 LM5171
PRODUCTION DATA
The UVLO pin serves as the Controller enable or disable pin. To use the UVLO pin to program undervoltage lockout control for the HV-port, LV-port, or VCC rail, see Section 6.4.2 for details.
There are two UVLO voltage thresholds. When the pin voltage is externally pulled below 1.25V, the LM5171 is in shutdown mode, in which all gate drivers are in the OFF state, all internal logic resets, and the IC draws less than 10µA through each of the HV and VCC pins.
When the UVLO pin voltage is pulled higher than 1.5V but lower than 2.5V, the LM5171 is in the initialization mode in which LDODRV pin turns on to control the external MOSFET to establish the VCC voltage at 9.0V, and the VDD at 5.0V and VREF at 3.5V. The DT/SD pin is pulled up to 1.2V, but the rest of the LM5171 remains off as long as EN1, EN2 are less than 1V, and/or DIR1 and DIR2 are invalid signals.
When the UVLO pin is pulled higher than 2.5V, which is the UVLO release threshold and the controller enable threshold, the LM5171 oscillator is activated, and the SYNCO pin gives out the phase shifted clock at the oscillator frequency, and the LM5171 is ready to operate. The SS/DEM1 and SS/DEM2 as well as LO1, LO2, HO1, and HO2 drivers remain off until the EN1, EN2, and DIR inputs command them to operate.