Apparatus for PWM gate drive circuit
A converter comprises a high side switch, a low side switch connected in series with the high switch, a gate drive circuit comprising a first drive port coupled to a gate of the high side switch, a second drive port coupled to a gate of the low side switch, an SRE input port and a PWM input port coupled to a PWM controller, wherein the PWM controller is selected from the group consisting of a first PWM controller having two complementary PWM outputs, a second PWM controller having a tri-state PWM output and a third PWM controller having a single PWM output.
1. A converter comprising:
a high side switch;
a low side switch connected in series with the high side switch;
a gate drive circuit comprising:
a first drive port coupled to a gate of the high side switch;
a second drive port coupled to a gate of the low side switch;
a control input port; and
a PWM input port having an input interface suitable for a first PWM controller having two complementary PWM outputs, a second PWM controller having a single PWM output generating a tri-state PWM fed into the PWM input port and a third PWM controller having a single PWM output fed into the PWM input port and a control logic output fed into the control input port.
2. The converter of claim 1 , wherein:
the first drive port is configured to generate a first gate signal in phase with a first PWM signal from the first PWM controller; and
the second drive port is configured to generate a second gate signal in phase with a second PWM signal from the first PWM controller, wherein the first PWM signal and the second PWM signal are two complementary control signals.
3. The converter of claim 1 , wherein:
the first drive port is configured to generate a first gate signal in phase with a first PWM signal from the second PWM controller; and
the second drive port is configured to generate a second gate signal complementary to the first gate signal.
4. The converter of claim 3 , wherein:
when the first PWM signal is in tri-state, both the first drive port and the second drive port are configured to generate a logic low state.
5. The converter of claim 1 , wherein:
in response to a logic high state at the control input port, the first drive port is configured to generate a first gate signal in phase with a first PWM signal from the third PWM controller; and
the second drive port is configured to generate a second gate signal complementary to the first gate signal.
6. The converter of claim 1 , wherein:
in response to a logic low state at the control input port, the first drive port is configured to generate a first gate signal in phase with a first PWM signal from the third PWM controller; and
the second drive port is configured to generate a logic low signal.
7. The converter of claim 1 , wherein:
the converter is a step-down dc/dc converter comprising:
a plurality of input capacitors coupled between an input of the converter and ground;
the high side switch connected in series with the low side switch, wherein the high side switch is coupled to input capacitors and the low side switch is coupled to ground; and
an output filter coupled to a common node of the high side switch and the low side switch.
8. The converter of claim 7 , wherein:
the output filter comprises an output inductor and a plurality of output capacitors.
9. An apparatus comprising:
a first gate drive port configured to generate a first gate drive signal;
a second gate drive port configured to generate a second gate drive signal, wherein the second gate drive signal and the first gate drive signal are complementary during normal operation;
a control input port; and
a PWM input port having an input interface suitable for a first PWM controller having two complementary PWM outputs connected to the PWM input port and the control input port respectively, a second PWM controller having a single tri-state PWM output connected to the PWM input port and a third PWM controller having a single PWM output and a logic output connected to the PWM input port and the control input port respectively.
10. The apparatus of claim 9 , further comprising:
a first switch having a gate coupled to the first gate drive port; and
a second switch have a gate coupled to the second gate drive port.
11. The apparatus of claim 10 , wherein:
the first switch and the second switch are connected in series.
12. The apparatus of claim 11 , wherein:
the first switch is a main switch of a step-down dc/dc converter; and
the second switch is a synchronous switch of the step-down dc/dc converter.
13. The apparatus of claim 9 , wherein:
the PWM input port is configured to receive a plurality of first PWM pulses;
the control input port is configured to receive a plurality of second PWM pulses, wherein the second PWM pulses are complementary to the first PWM pulses;
the first gate drive port is configured to generate the first gate drive signal in phase with the first PWM pulses; and
the second gate drive port is configured to generate the second gate drive signal in phase with the second PWM pulses.
14. The apparatus of claim 9 , wherein:
the PWM input port is configured to receive a tri-state signal and a PWM signal.
15. The apparatus of claim 14 , wherein:
the first gate drive port is configured to generate the first gate drive signal in phase with the PWM signal when the PWM input port is configured to receive the PWM signal; and
the second gate drive port is configured to generate the second gate drive signal complementary to the first gate drive signal when the PWM input port is configured to receive the PWM signal.
16. The apparatus of claim 14 , wherein:
the first gate drive port is configured to generate a logic low signal when the PWM input port is configured to receive the tri-state signal; and
the second gate drive port is configured to generate the logic low signal when the PWM input port is configured to receive the tri-state signal.
17. A method comprising:
detecting a first signal at a PWM port and a second signal at a control port of a gate drive circuit, wherein the gate drive circuit includes an input interface suitable for a first PWM controller having two complementary PWM outputs connected to the PWM port and the control port respectively, a second PWM controller having a tri-state PWM output connected to the PWM port and a third PWM controller having a single PWM output and a logic output connected to the PWM port and the control port respectively;
determining an operation mode of the gate drive circuit based upon the first signal and the second signal; and
generating a first gate drive signal at a first gate drive port and a second gate drive signal at a second gate drive port based upon the first signal the second signal, wherein the first gate drive signal and the second gate drive signal are complementary signals.
18. The method of claim 17 , further comprising:
detecting a plurality of first PWM pulses at the PWM port and a plurality of second PWM pulses at the control port, wherein the second PWM pulses are complementary to the first PWM pulses;
generating the first gate drive signal in phase with the first PWM pulses; and
generating the second gate drive signal in phase with the second PWM pulses.
19. The method of claim 17 , further comprising:
detecting a tri-state signal at the PWM port;
generating a first logic low signal at the first gate drive port; and
generating a second logic low signal at the second gate drive port.
20. The method of claim 19 , further comprising:
in response to a control signal transition from the tri-state signal to a PWM signal, generating the first gate drive signal in phase with the PWM signal; and
generating the second gate drive signal complementary to the first gate drive signal.