System and method for preventing cross-conduction when switching circuitry during voltage regulation
View Patent ↗To prevent cross-conduction when switching switches in switching circuitry for voltage regulation, a dead time may be maintained between turning off a switch and turning on a switch. The dead time may be determined based on a switching transition voltage and a voltage of the switching circuitry and may be implemented using a timer.
1. A voltage regulator comprising:
switching circuitry including a first switching transistor and a second switching transistor, the first switching transistor and the second switching transistor electrically connected in series, a point of electrical connection between the first switching transistor and the second switching transistor providing a phase node of the switching circuitry; and
switching logic configured to:
when the first switching transistor is in an on state and the second switching transistor is in an off state, monitor a switching transition voltage of the first switching transistor;
when the switching transition voltage passes a switching transition voltage threshold for the switching transition voltage of the first switching transistor, monitor a phase node voltage of the phase node, wherein the phase node voltage corresponds to a body diode voltage of the first switching transistor; and
when the phase node voltage passes a phase node voltage threshold for the phase node voltage, turn on the second switching transistor after a dead time determined based on a temporal duration between the switching transition voltage passing the switching transition voltage threshold and the phase node voltage passing the phase node voltage threshold.
2. The voltage regulator of claim 1 , wherein the switching transition voltage is a gate voltage of the first switching transistor.
3. The voltage regulator of claim 1 , wherein the first switching transistor is a high side transistor.
4. The voltage regulator of claim 1 , wherein the first switching transistor is a low side transistor.
5. The voltage regulator of claim 1 , wherein the switching logic is configured to receive a switching control signal and cause the first switching transistor and the second switching transistor to transition states based upon the switching control signal.
6. The voltage regulator of claim 1 , further comprising a timer, wherein the timer is incremented over the temporal duration to determine the dead time.
7. The voltage regulator of claim 6 , wherein the timer is decremented subsequent to the phase node voltage passing the phase node voltage threshold to determine the dead time.
8. The voltage regulator of claim 6 , further comprising a comparator, wherein the comparator is configured to compare the phase node voltage with the phase voltage threshold to determine when the phase node voltage passes the phase node voltage threshold.
9. The voltage regulator of claim 1 , wherein if the phase node voltage fails to pass the phase node voltage threshold, a default dead time is set.
10. A method of switching during voltage regulation, the method comprising:
receiving a switching signal when a first switching transistor is in an on state and a second switching transistor is in an off state;
determining when a first gate voltage of a first gate of the first switching transistor passes a gate voltage threshold for the first gate voltage;
when the first gate voltage passes the gate voltage threshold, monitor a phase node voltage defined by switching the first switching transistor and the second switching transistor, wherein the phase node voltage corresponds to a body diode voltage of the first switching transistor; and
when the phase node voltage passes a phase node voltage threshold for the phase node voltage, turn on the second switching transistor after a dead time determined based on a temporal duration between the first gate voltage passing the gate voltage threshold and the phase node voltage passing the phase node voltage threshold.
11. The method of claim 10 , wherein the first switching transistor is a high side transistor.
12. The method of claim 10 , wherein the first switching transistor is a low side transistor.
13. The method of claim 10 , wherein the phase node voltage threshold is based on a body diode voltage of the first switching transistor.
14. A voltage regulator comprising:
switching circuitry including a first switching transistor and a second switching transistor, the first switching transistor and the second switching transistor electrically connected in series, a point of electrical connection between the first switching transistor and the second switching transistor providing a phase node of the switching circuitry; and
switching logic configured to:
when the first switching transistor is in an on state and the second switching transistor is in an off state, monitor a first gate voltage of a first gate of the first switching transistor;
when the first gate voltage passes a gate voltage threshold, monitor the phase node voltage and integrate values of the phase voltage over time to derive an integration sum; and
when the integration sum exceeds an integration threshold, turn on the second switching transistor after a dead time determined based on a temporal duration between the first gate voltage passing the gate voltage threshold and the integration sum exceeding the integration threshold.
15. The voltage regulator of claim 14 , further comprising an integrator, wherein the integrator is configured to integrate values of the phase node voltage over time to derive the integration sum.
16. The voltage regulator of claim 14 , wherein the first switching transistor is a high side transistor.
17. The voltage regulator of claim 14 , wherein the first switching transistor is a low side transistor.