JAJSML7B March 2013 – August 2021 TPS53511
PRODUCTION DATA
The main control loop of the TPS53511 is an adaptive on-time pulse width modulation (PWM) controller that supports a proprietary D-CAP2™ mode control. D-CAP2™ mode control combines constant on-time control with an internal compensation circuit for pseudo-fixed frequency and low external component count configuration with both low-ESR and ceramic output capacitors. It is stable even with virtually no ripple at the output.
At the beginning of each cycle, the high-side MOSFET is turned on. This MOSFET is turned off after internal one shot timer expires. This one shot timer is set by the converter input voltage, VVIN, and the output voltage, VVO, to maintain a pseudo-fixed frequency over the output voltage range, hence it is called adaptive on-time control. The one-shot timer is reset and the high-side MOSFET is turned on again when the feedback voltage falls below the reference voltage. An internal ramp is added to the reference voltage to simulate output ripple, eliminating the need for ESR-induced output ripple from D-CAP2™ mode control.