Body-diode conduction detector for adaptive controlling of the power stage of power converters

A method comprising:

• configuring a first portion of a circuit as a voltage follower, wherein an output signal at an output terminal of the first portion of the circuit is configured to track a reference voltage;
• tracking the reference voltage during a first phase of circuit operation, wherein the first phase comprises a beginning and an end;
• storing, by a second portion of the circuit at the end of the first phase, a voltage on a capacitor, wherein the stored voltage on the capacitor comprises a sum of an input voltage at the end of the first phase plus the reference voltage,
• wherein the capacitor comprises a first terminal and a second terminal,
• wherein a first switch connects the first terminal of the capacitor to an input voltage during the first phase and a second phase;
• and
• during the second phase of circuit operation:
• configuring the first portion of the circuit as a voltage comparator, wherein the output signal at the output terminal of the first portion of the circuit comprises a plurality of logic levels;
• comparing a sum of the stored voltage plus the input voltage to the reference voltage, wherein the input voltage is changing during the second phase;
• in response to the sum of the stored voltage plus the input voltage being more negative than the reference voltage, toggling the output signal of the first portion of the circuit from a first logic level to a second logic level;
• and
• disconnecting, by the first switch, the first terminal of the capacitor from the input voltage during a third phase.

A system comprising a controller circuit configured to drive a power stage of a switched mode power supply, the controller circuit comprising:

• a driver element configured to drive at least one switch of the power stage;
• a body diode conduction detector (BDCD) circuit comprising:
• a first switch;
• a capacitor configured to store a voltage at an end of a first phase,
• wherein the capacitor comprises a first terminal and a second terminal;
• wherein the stored voltage comprises a sum of a reference voltage plus a switching node voltage of the power stage at the end of the first phase, and
• wherein the first switch connects the first terminal of the capacitor to the switching node voltage during the first phase and a second phase and the first switch disconnects the first terminal of the capacitor from the input voltage during a third phase;
• and
• an operational amplifier comprising an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the second terminal of the capacitor connects to the inverting input terminal, and wherein the reference voltage connects to a non-inverting input of the operational amplifier, the operational amplifier configured:
• as a voltage follower during the first phase, wherein a second switch connects the output terminal to the inverting input terminal during the first phase;
• and
• as a comparator during a second phase, wherein the second switch disconnects the output terminal from the inverting input terminal during the second phase, the operational amplifier configured to:
• compare a sum of the stored voltage plus the switching node voltage to the reference voltage, wherein the switching node voltage is changing during the second phase;
• and
• in response to the sum of the switching node voltage plus the stored voltage being more negative than the reference voltage, toggle an output signal of the operational amplifier from a first logic level to a second logic level.