ZHCS688I November 2011 – March 2018 TPS65217
PRODUCTION DATA.
The converter starts to go to the 100% duty-cycle mode after the input voltage (VIN) comes close to the nominal output voltage. To keep the output voltage steady, the high-side MOSFET is turned on 100% for one or more cycles. As the VIN voltage decreases further, the high-side MOSFET is turned on completely. In this case, the converter offers a low input-to-output voltage difference which is particularly useful in battery-powered applications to achieve longest operation time by taking full advantage of the whole battery voltage range.
Use Equation 2 to calculate the minimum input voltage to keep regulation (VIN,MIN) which depends on the load current and output voltage.
where