GENERATION OF POSITIVE AND NEGATIVE SWITCH GATE CONTROL VOLTAGES
A technique for powering gate drivers in a half-bridge configuration uses a single external power supply to power each gate driver. A single on-chip regulator regulates the positive turn-on voltage for each switch. The regulator overhead, is also used as the negative voltage for turn-off, thus transferring the low-frequency variation of the external power supply to the negative turn-off voltage. Accordingly, a single on-chip regulator generates both the positive turn-on voltage and the negative turn-off voltage. In at least one embodiment, reuse of the switch turn-off current further reduces on-chip power dissipation. The on-chip regulator's output filter capacitor discharges during turn-on of the external power switching device. During turn-off, the current that discharges the switch gate capacitance recharges the regulator filter capacitor.
1 . (canceled)
2 . A gate driver comprising:
a first power supply terminal configured to receive a first power supply voltage from a power supply;
a second power supply terminal configured to receive a second power supply voltage from the power supply;
a voltage regulator output configured to provide a regulated voltage; and
a programmable voltage regulator configured to generate the regulated voltage, the regulated voltage having a level between a first level of the first power supply voltage and a second level of the second power supply voltage, and the regulated voltage being based on a voltage level for a difference between the first power supply voltage and the regulated voltage.
3 . The gate driver of claim 2 wherein the voltage level is selectable using a programmable resistor or a programmable voltage reference.
4 . The gate driver of claim 3 wherein the programmable resistor or the programmable voltage reference is programmed during initialization of the gate driver.
5 . The gate driver of claim 2 wherein the programmable voltage regulator regulates a positive turn-on voltage.
6 . The gate driver of claim 2 further comprising a pull-up control circuit configured to pull up a voltage on an output node of the gate driver to turn on a drive device and a pull-down control circuit configured to pull down the voltage on the output node to turn off the drive device.
7 . The gate driver of claim 2 wherein the programmable voltage regulator includes a differential-to-single-ended voltage converter configured to generate a single-ended voltage corresponding to a voltage drop across the first power supply terminal and the voltage regulator output.
8 . The gate driver of claim 7 wherein the programmable voltage regulator further includes a comparator configured to generate a bias control signal based on a comparison of the single-ended voltage to a reference voltage.
9 . The gate driver of claim 8 wherein the programmable voltage regulator further includes a bias current generator configured to provide a bias current to a node coupled to the voltage regulator output according to the bias control signal, the bias current being configured to provide a startup current to charge a first external capacitor to the voltage level and the bias current is configured to provide a maintenance current to maintain the first external capacitor at the voltage level.
10 . The gate driver of claim 7 wherein the differential-to-single-ended voltage converter includes an operational amplifier.
11 . A gate driver system comprising:
a power supply; and
a first gate driver and a second gate driver, each gate driver including a first power supply terminal and a second power supply terminal connected to the power supply, a voltage regulator output configured to provide a regulated voltage, and a voltage regulator configured to generate the regulated voltage, the regulated voltage having a level between a first level of a first power supply voltage received from the power supply and a second level of a second power supply voltage received from the power supply, and the regulated voltage being based on a voltage level for a difference between the first power supply voltage and the regulated voltage.
12 . The gate driver system of claim 11 wherein the power supply includes a rectifier diode connected to a first output of the power supply configured to output the first power supply voltage.
13 . The gate driver system of claim 11 wherein the power supply includes a direct current to direct current controller configured to regulate a positive supply voltage to a target level.
14 . The gate driver system of claim 11 further comprising a first regulator filtering capacitor between the first power supply terminal and the second power supply terminal of the first gate driver, and a second regulator filtering capacitor between the first power supply terminal and an output node of the first gate driver.
15 . The gate driver system of claim 11 wherein the first gate driver further includes a pull-up control circuit configured to pull up a voltage on an output node of the first gate driver to turn on a drive device and a pull-down control circuit configured to pull down the voltage on the output node to turn off the drive device.
16 . The gate driver system of claim 11 wherein the voltage regulator includes a differential-to-single-ended voltage converter configured to generate a single-ended voltage corresponding to a voltage drop across the first power supply terminal and the voltage regulator output.
17 . The gate driver system of claim 16 wherein the voltage regulator further includes:
a comparator configured to generate a bias control signal based on a comparison of the single-ended voltage to a reference voltage; and
a bias current generator configured to provide a bias current to a node coupled to the voltage regulator output according to the bias control signal, the bias current being configured to provide a startup current to charge a first external capacitor to the voltage level and the bias current is configured to provide a maintenance current to maintain the first external capacitor at the voltage level.
18 . The gate driver system of claim 16 wherein the differential-to-single-ended voltage converter includes an operational amplifier.
19 . A motor controller configured to control a motor, the motor controller comprising:
a processor configured to output a control signal; and
a gate driver system configured to receive the control signal and to controllably supply power to the motor, the gate driver system including a power supply, a first gate driver and a second gate driver, each gate driver including a first power supply terminal and a second power supply terminal connected to the power supply, a voltage regulator output configured to provide a regulated voltage, and a voltage regulator configured to generate the regulated voltage, the regulated voltage having a level between a first level of a first power supply voltage received from the power supply and a second level of a second power supply voltage received from the power supply, and the regulated voltage being based on a voltage level for a difference between the first power supply voltage and the regulated voltage.
20 . The motor controller of claim 19 wherein the first gate driver further includes a pull-up control circuit configured to pull up a voltage on an output node of the first gate driver to turn on the motor and a pull-down control circuit configured to pull down the voltage on the output node to turn off the motor.
21 . The motor controller of claim 19 further comprising:
a primary-side integrated circuit configured to receive the control signal from the processor and to provide the control signal to a secondary-side integrated circuit across an isolation barrier; and
the secondary-side integrated circuit including the voltage regulator.