SLVSD44A September 2017 – July 2018 TPS63710
PRODUCTION DATA.
The discharge circuit keeps the output voltage at 0 V when the TPS63710 is disabled. The TPS63710 only begins the start-up cycle when the output voltage is between +300 mV to -300 mV to ensure a proper start-up. When the output voltage is not in this range, the device keeps the discharge switch on and waits until the voltage is within the window.
When the device is enabled, the internal reference is powered up. After the startup delay time when the CCP capacitor is pre-charged, the device enters soft-start, starts switching and ramps down the output voltage. Soft-start is achieved by ramping the reference voltage, hence the output voltage, to its nominal value. This ramp time is defined by an external capacitor connected to the CAP pin. The capacitor is charged with typically 100 µA by an internal current source. The ramp time is defined in Equation 2.