JAJSG85 September 2018 LM2734-Q1
PRODUCTION DATA.
In applications where both VIN and VOUT are greater than 5.5 V, or less than 3 V, CBOOST cannot be charged directly from these voltages. If VIN is greater than 5.5 V, CBOOST can be charged from VIN minus a zener voltage by placing a zener diode D3 in series with D2. When using a series zener diode from the input, ensure that the regulation of the input supply doesn’t create a voltage that falls outside the recommended VBOOST voltage.