High side switch gate drive apparatus and control method
An apparatus includes a high side switch connected between an input voltage bus and a load terminal, the load terminal being configured to be coupled to a load, a high side gate drive circuit configured to generate a gate drive signal for the high side switch, and a resonance suppression circuit having a first terminal connected to a gate of the high side switch, and a second terminal connected to the load terminal, wherein after a predetermined delay counting from a falling edge of an enable signal applied to the high side gate drive circuit, the resonance suppression circuit is configured to be active, and after a voltage on the load terminal rises above a ground voltage potential for a first time, the resonance suppression circuit is configured to pull a voltage on the gate of the high side switch down to a low voltage.
1 . An apparatus comprising:
a high side switch connected between an input voltage bus and a load terminal, the load terminal being configured to be coupled to a load;
a high side gate drive circuit configured to generate a gate drive signal for the high side switch; and
a resonance suppression circuit having a first terminal connected to a gate of the high side switch, and a second terminal connected to the load terminal,
wherein the resonance suppression circuit is configured to enter an enabled state in response to a second enable signal, the second enable signal being asserted upon expiration of a predetermined delay duration counting from a falling edge of a first enable signal applied to the high side gate drive circuit,
and wherein, subsequent to entering the enabled state and in response to detecting that a voltage on the load terminal rises above a ground voltage potential for a first time, the resonance suppression circuit is configured to actuate a switch to pull a voltage on the gate of the high side switch down to a low voltage,
and wherein a first drain/source terminal of the switch is directly connected to the gate of the high side switch, and a second drain/source terminal of the switch is coupled to ground.
2 . The apparatus of claim 1 , wherein the resonance suppression circuit comprises:
the switch, wherein the switch is a pull-down switch;
a first resistor coupled between the gate of the pull-down switch and the load terminal; and
an enable switch coupled to the gate of the pull-down switch.
3 . The apparatus of claim 2 , further comprising a second resistor and a first Zener diode, wherein:
the first Zener diode is coupled between a gate of the pull-down switch and ground;
the pull-down switch and the second resistor are connected in series between the gate of the high side switch and ground; and
the enable switch is connected between the gate of the pull-down switch and ground, and wherein:
the high side switch is configured to be disabled from powering the load in response to the falling edge of the first enable signal; and
the enable switch is configured to be turned off after the predetermined delay counting from the falling edge of the first enable signal.
4 . The apparatus of claim 2 , further comprising a second resistor and a first Zener diode, wherein:
the first Zener diode is coupled between a gate of the pull-down switch and ground;
the pull-down switch and the second resistor are connected in series between the gate of the high side switch and ground; and
the enable switch and the first resistor are connected in series between the gate of the pull-down switch and the load terminal, and wherein:
the high side switch is configured to be disabled from powering the load in response to the falling edge of the first enable signal; and
the enable switch is configured to be turned on after the predetermined delay counting from the falling edge of the first enable signal.
5 . The apparatus of claim 2 , further comprising a first Zener diode, wherein:
the first Zener diode is coupled between a gate of the pull-down switch and ground;
the pull-down switch has a first drain/source terminal connected to the gate of the high side switch and a second drain/source terminal connected to ground; and
the enable switch is connected between the gate of the pull-down switch and ground, and wherein:
the high side switch is configured to be disabled from powering the load in response to the falling edge of the first enable signal; and
the enable switch is configured to be turned off after the predetermined delay counting from the falling edge of the first enable signal.
6 . The apparatus of claim 2 , further comprising a second resistor, a plurality of resistor-switch networks connected in parallel with the second resistor and a first Zener diode, wherein:
the first Zener diode is coupled between a gate of the pull-down switch and ground;
the pull-down switch and the second resistor are connected in series between the gate of the high side switch and ground, and wherein the plurality of resistor-switch networks is configured such that a current flowing through the pull-down switch is dynamically adjustable; and
the enable switch is connected between the gate of the pull-down switch and ground, and wherein:
the high side switch is configured to be disabled from powering the load in response to the falling edge of the first enable signal; and
the enable switch is configured to be turned off after the predetermined delay counting from the falling edge of the first enable signal.
7 . The apparatus of claim 2 , further comprising a second resistor, a third resistor, an auxiliary switch and a first Zener diode, wherein:
the first Zener diode is coupled between a gate of the pull-down switch and ground;
the pull-down switch and the second resistor are connected in series between the gate of the high side switch and ground;
the auxiliary switch and the third resistor are connected in series between the gate of the pull-down switch and the load terminal, wherein the auxiliary switch is configured such that a slew rate of a voltage on the gate of the pull-down switch is dynamically adjustable; and
the enable switch is connected between the gate of the pull-down switch and ground, and wherein:
the high side switch is configured to be disabled from powering the load in response to the falling edge of the first enable signal; and
the enable switch is configured to be turned off after the predetermined delay counting from the falling edge of the first enable signal.
8 . The apparatus of claim 2 , further comprising an auxiliary switch and a first Zener diode, wherein:
the first Zener diode is coupled between a gate of the pull-down switch and ground;
the auxiliary switch is connected in parallel with the first resistor, wherein the auxiliary switch is configured such that a slew rate of a voltage on the gate of the pull-down switch is dynamically adjustable; and
the enable switch is connected between the gate of the pull-down switch and ground, and wherein:
the high side switch is configured to be disabled from powering the load in response to the falling edge of the first enable signal; and
the enable switch is configured to be turned off after the predetermined delay counting from the falling edge of the first enable signal.
9 . The apparatus of claim 2 , further comprising a first Zener diode and a plurality of diodes, wherein:
the plurality of diodes and the first Zener diode are connected in series between the gate of the pull-down switch and ground.
10 . The apparatus of claim 1 , wherein:
the load is an inductive load; and
the low voltage is approximately equal to the ground voltage potential.
11 . A method comprising:
in response to a falling edge of a first enable signal, configuring a high side switch to be turned off, wherein the high side switch is connected between an input voltage bus and a load terminal configured to be coupled to a load;
configuring a resonance suppression circuit to enter an enabled state in response to a second enable signal, the second enable signal being asserted upon expiration of a predetermined delay duration counting from the falling edge of the first enable signal; and
after entering the enabled state and in response to detecting that a voltage on the load terminal rises above a ground voltage potential for a first time, configuring the resonance suppression circuit to actuate a switch to pull a voltage on the gate of the high side switch down to a low voltage, and wherein a first drain/source terminal of the switch is directly connected to the gate of the high side switch, and a second drain/source terminal of the switch is coupled to ground.
12 . The method of claim 11 , wherein the resonance suppression circuit comprises:
the switch, wherein the switch is a pull-down switch;
a first resistor coupled between the gate of the pull-down switch and the load terminal; and
an enable switch coupled between the gate of the pull-down switch and ground.
13 . The method of claim 12 , further comprising:
after the predetermined delay counting from the falling edge of the first enable signal, configuring the enable switch to be turned off and configuring the pull-down switch to be turned on to pull the voltage on the gate of the high side switch down to the low voltage, wherein the pull-down switch is turned on after the voltage on the load terminal rises above a turn-on threshold of the pull-down switch.
14 . The method of claim 11 , wherein the resonance suppression circuit comprises:
the switch, wherein the switch is a pull-down switch; and
an enable switch and a first resistor coupled between the gate of the pull-down switch and the load terminal.
15 . The method of claim 14 , further comprising:
after the predetermined delay counting from the falling edge of the first enable signal, configuring the enable switch to be turned on and configuring the pull-down switch to be turned on to pull the voltage on the gate of the high side switch down to the low voltage after the voltage on the load terminal rises above a turn-on threshold of the pull-down switch.
16 . The method of claim 11 , wherein the resonance suppression circuit comprises:
the switch, wherein the switch is a pull-down switch;
an enable switch coupled between the gate of the pull-down switch and ground; and
a MOSFET switch coupled between the gate of the pull-down switch and the load terminal.
17 . The method of claim 16 , further comprising:
configuring the MOSFET switch to be turned off before the falling edge of the first enable signal;
after the predetermined delay counting from the falling edge of the first enable signal, configuring the enable switch to be turned off and configuring the pull-down switch to be turned on to pull the voltage on the gate of the high side switch down to the low voltage; and
after the predetermined delay counting from the falling edge of the first enable signal, configuring the MOSFET switch to function as a variable resistor such that a slew rate of a voltage on the gate of the pull-down switch is dynamically adjustable.
18 . A driver comprising:
a high side gate drive circuit configured to generate a gate drive signal for a high side switch connected between an input voltage bus and a load terminal configured to be coupled to a load; and
a resonance suppression circuit connected between a gate of the high side switch and the load terminal, wherein the resonance suppression circuit is configured to enter an enabled state in response to a second enable signal, the second enable signal being asserted upon expiration of a predetermined delay duration counting from a falling edge of a first enable signal applied to the high side gate drive circuit, and wherein, subsequent to entering the enabled state and in response to detecting that a voltage on the load terminal rises above a ground voltage potential for a first time, the resonance suppression circuit is configured to actuate a switch to pull a voltage on the gate of the high side switch down to a low voltage, and wherein a first drain/source terminal of the switch is directly connected to the gate of the high side switch, and a second drain/source terminal of the switch is coupled to ground.
19 . The driver of claim 18 , wherein:
the resonance suppression circuit comprises:
the switch, wherein the switch is a pull-down switch;
at least a diode coupled between a gate of the pull-down switch and ground;
a first resistor coupled between the gate of the pull-down switch and the load terminal; and
an enable switch coupled between the gate of the pull-down switch and ground; and
the high side gate drive circuit comprises:
a first bias switch and a second bias switch coupled in series between a bias voltage bus and the load terminal, and wherein a common node of the first bias switch and the second bias switch is connected to the gate of the high side switch; and
a gate drive resistor connected between the gate of the high side switch and the load terminal.
20 . The driver of claim 19 , further comprising a second Zener diode, wherein:
the at least a diode is a first Zener diode;
the second Zener diode is connected between the input voltage bus and the gate of the high side switch;
the load is an inductive load; and
the low voltage is approximately equal to the ground voltage potential.
21 . The driver of claim 19 , further comprising a second Zener diode, wherein:
the at least a diode is a first Zener diode;
the second Zener diode is connected between the input voltage bus and the load terminal;
the load is an inductive load; and
the low voltage is approximately equal to the ground voltage potential.