# US 9,379,696 B2 · High voltage bootstrap gate driving apparatus

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- Number: US 9,379,696 B2
- Document ID: US9379696B2
- Status: Granted
- Kind: B2
- Application number: 14/294,176
- Filed: 2014-06-03
- Published: 2015-10-29
- Granted: 2016-06-28
- Earliest claimed: 2014-04-29
- Assignees: Maxchip Electronics Corp.
- Applicants: Maxchip Electronics Corp.
- Inventors: Ming-Chi Kuo; Tsung-Chih Tsai; Jen-Yao Hsu
- Web page: https://patentgrep.com/patent/US9379696B2

## CPC

- H03K 17/145: {in field-effect transistor switches}
- H03K 17/063: {in field-effect transistor switches}
- H03K 17/162: {without feedback from the output circuit to the control circuit}
- H03K 17/6871: {the output circuit comprising more than one controlled field-effect transistor}
- H03K 2017/6875: {using self-conductive, depletion FETs}
- H03K 2217/0054: Gating switches, e.g. pass gates
- H03K 2217/0081: Power supply means, e.g. to the switch driver
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A high voltage bootstrap gate driving apparatus is provided. The gate driving apparatus includes a high-end transistor, a low-end transistor, a buffer, a boost capacitor, and a high voltage depletion transistor. The high-end transistor receives a first power voltage. The buffer provides a high-end driving signal to the high-end transistor according to a bias voltage. The boost capacitor is serial coupled between a base voltage and a bias voltage. A first end of the depletion transistor is coupled to a second power voltage, a second end of the depletion transistor is coupled to the bias voltage, and a control end of the depletion transistor receives the reference ground voltage.

## Claims

### Claim 1

A high voltage bootstrap gate driving apparatus, comprising:
a high-end transistor, having a first end, a second end, and a control end, wherein the first end of the high-end transistor receives a first power voltage;
a low-end transistor, having a first end, a second end, and a control end, wherein the first end of the low-end transistor is coupled to the second end of the high-end transistor, and the second end of the low-end transistor is coupled to a reference ground voltage;
a buffer, providing a high-end driving signal to the control end of the high-end transistor according to a bias voltage, and providing a low-end driving signal to the control end of the low-end transistor;
a boost capacitor, serial coupled between a base voltage and the bias voltage, wherein the base voltage is produced at the second end of the high-end transistor;
a depletion transistor, having a first end, a second end, and a control end, wherein the first end of the depletion transistor is coupled to a second power voltage, the second end of the depletion transistor is coupled to the bias voltage, and the control end of the depletion transistor receives the reference ground voltage,
wherein the buffer, the high-end transistor, the low-end transistor, the boost capacitor and the depletion transistor are disposed in an integrated circuit,
wherein as the low-end transistor is conductive according to the low-end driving signal, the high-end transistor is disconnected, and the second power voltage charges the boost capacitor through the depletion transistor, so that the bias voltage is equal to a threshold turn-off voltage of the depletion transistor, wherein when the high-end transistor is conductive according to the high-end driving signal, the low-end transistor is disconnected, and the bias voltage is pulled up to be equal to the first power voltage plus the threshold turn-off voltage.

### Claim 2 (depends on 1)

The high voltage bootstrap gate driving apparatus as claimed in claim 1, wherein the depletion transistor is an N-type depletion transistor or an N-type junction field effect transistor.

### Claim 3 (depends on 2)

The high voltage bootstrap gate driving apparatus as claimed in claim 2, wherein a base of the depletion transistor is coupled to the reference ground voltage.

### Claim 4 (depends on 1)

The high voltage bootstrap gate driving apparatus as claimed in claim 1, wherein the high-end transistor and the low-end transistor are N-type transistors.

### Claim 5 (depends on 1)

The high voltage bootstrap gate driving apparatus as claimed in claim 1, wherein the buffer comprises:
a high-end buffer, coupled to the second end of the depletion transistor, the control end of the high-end transistor, and the second end of the high-end transistor, wherein the high-end buffer adjusts a voltage level of the high-end driving signal according to the bias voltage; and
a low-end buffer, coupled to the control end of the low-end transistor, and providing the low-end driving signal.

### Claim 6 (depends on 5)

The high voltage bootstrap gate driving apparatus as claimed in claim 5, further comprising:
a core circuit, coupled to the high-end buffer and the low-end buffer, the core circuit provides a high-end control signal and a low-end control signal to the high-end buffer and the low-end buffer respectively,
wherein the high-end buffer and the low-end buffer produce the high-end driving signal and the low-end driving signal respectively according to the high-end control signal and the low-end control signal respectively.

### Claim 7 (depends on 1)

The high voltage bootstrap gate driving apparatus as claimed in claim 1, wherein both the high-end driving signal and the low-end driving signal are pulse width modulation signals.

### Claim 8 (depends on 1)

The high voltage bootstrap gate driving apparatus as claimed in claim 1, wherein a voltage level of the first power voltage is greater than a voltage level of the second power voltage.

### Claim 9 (depends on 1)

The high voltage bootstrap gate driving apparatus as claimed in claim 1, wherein a reverse breakdown voltage of the depletion transistor is greater than a voltage level of the first power voltage plus a voltage level of a threshold turn-off voltage of the depletion transistor.

### Claim 10

A high voltage bootstrap gate driving apparatus, comprising:
a high-end transistor, having a first end, a second end, and a control end, wherein the first end of the high-end transistor receives a first power voltage;
a low-end transistor, having a first end, a second end, and a control end, wherein the first end of the low-end transistor is coupled to the second end of the high-end transistor, and the second end of the low-end transistor is coupled to a reference ground voltage;
a buffer, providing a high-end driving signal to the control end of the high-end transistor according to a bias voltage, and providing a low-end driving signal to the control end of the low-end transistor;
a boost capacitor, serial coupled between a base voltage and the bias voltage, wherein the base voltage is produced at the second end of the high-end transistor;
a depletion transistor, having a first end, a second end, and a control end, wherein the first end of the depletion transistor is coupled to a second power voltage, the second end of the depletion transistor is coupled to the bias voltage, and the control end of the depletion transistor receives the reference ground voltage,
wherein the buffer, the high-end transistor, the low-end transistor, the boost capacitor and the depletion transistor are disposed in an integrated circuit,
wherein a reverse breakdown voltage of the depletion transistor is greater than a voltage level of the first power voltage plus a voltage level of a threshold turn-off voltage of the depletion transistor.