# US 11,121,682 B1 · Single-stage boost class-D amplifier

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- Number: US 11,121,682 B1
- Document ID: US11121682B1
- Status: Granted
- Kind: B1
- Application number: 17/012,072
- Filed: 2020-09-04
- Granted: 2021-09-14
- Earliest claimed: 2020-09-04
- Assignees: Elite Semiconductor Microelectronics Technology Inc.
- Applicants: Elite Semiconductor Microelectronics Technology Inc.
- Inventors: Che-Wei Hsu; Wun-Long Yu; Deng-Yao Shih
- Web page: https://patentgrep.com/patent/US11121682B1

## CPC

- H03F 3/2171: {with field-effect devices (H03F3/2173 - H03F3/2178 take precedence)}
- H03F 3/2173: {of the bridge type}
- H03F 3/183: with semiconductor devices only
- H03F 2200/03: the amplifier being designed for audio applications
- H03F 2200/156: One or more switches are realised in the feedback circuit of the amplifier stage
- H03F 2200/351: Pulse width modulation being used in an amplifying circuit
- H03F: AMPLIFIERS

## Abstract

A boost class-D amplifier includes a PWM modulator, a boost level controller coupled to the PWM modulator, a pre-driver coupled to the PWM modulator and the boost level controller, a system voltage source, an inductor coupled to the system voltage source, a first switch, a second switch, a third switch, a fourth switch, a first diode coupled between the third switch and a voltage ground, a second diode coupled between the fourth switch and the voltage ground, and a capacitor coupled between the first switch and the fourth switch. The PWM modulator is for receiving an input signal and generating a first modulated signal accordingly. The boost level controller is for receiving the first modulated signal and generating a second modulated signal accordingly. The pre-driver is for receiving the first modulated signal and the second modulated signal and generating control signals accordingly.

## Claims

### Claim 1

A boost class-D amplifier comprising:
a PWM (pulse width modulation) modulator configured to receive an input signal and generate a first modulated signal accordingly;
a boost level controller coupled to the PWM modulator, configured to receive the first modulated signal and generate a second modulated signal accordingly;
a pre-driver coupled to the PWM modulator and the boost level controller and configured to receive the first modulated signal and the second modulated signal and generate a first control signal, a second control signal, a third control signal and a forth control signal accordingly;
a system voltage source configured to provide a system voltage;
an inductor coupled to the system voltage source;
a first switch comprising:
a first terminal coupled to the inductor;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the first control signal;
a second switch comprising:
a first terminal coupled to the inductor;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the second control signal;
a third switch comprising:
a first terminal coupled to the second terminal of the first switch;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the third control signal;
a fourth switch comprising:
a first terminal coupled to the second terminal of the second switch;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the fourth control signal;
a first diode coupled between the second terminal of the third switch and a voltage ground;
a second diode coupled between the second terminal of the fourth switch and the voltage ground; and
a capacitor coupled between the second terminal of the first switch and the first terminal of the fourth switch.

### Claim 2 (depends on 1)

The boost class-D amplifier of claim 1 further comprising a speaker coupled between the second terminal of the first switch and the first terminal of the fourth switch.

### Claim 3 (depends on 1)

The boost class-D amplifier of claim 1, wherein the first switch, the second switch, the third switch, and the fourth switch are bipolar junction transistors.

### Claim 4 (depends on 1)

The boost class-D amplifier of claim 1, wherein the first switch, the second switch, the third switch, and the fourth switch are metal oxide semiconductor field effect transistor (MOSFET).

### Claim 5 (depends on 1)

The boost class-D amplifier of claim 1, wherein the first control signal and the second control signal are complementary.

### Claim 6 (depends on 5)

The boost class-D amplifier of claim 5 wherein when the first control signal has a high voltage, the second control signal has a low voltage, the third control signal has a high frequency PWM signal and the fourth control signal has a high voltage.

### Claim 7 (depends on 5)

The boost class-D amplifier of claim 5 wherein when the first control signal has a low voltage, the second control signal has a high voltage, the third control signal has a high voltage and the fourth control signal has the high frequency PWM signal.

### Claim 8

A boost class-D amplifier comprising:
a PWM (pulse width modulation) modulator, configured to receive an input signal and generate a first modulated signal;
a boost level controller coupled to the PWM modulator, configured to receive the first modulated signal and output a second modulated signal;
a pre-driver coupled to the PWM modulator and the boost level controller;
a system voltage source, configured to provide a system voltage;
an inductor coupled to the system voltage source;
a first switch comprising:
a first terminal coupled to the inductor;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the first control signal;
a second switch comprising:
a first terminal coupled to the inductor;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the second control signal;
a third switch comprising:
a first terminal coupled to the second terminal of the first switch;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the third control signal;
a fourth switch comprising:
a first terminal coupled to the second terminal of the second switch;
a second terminal; and
a control terminal coupled to the pre-driver and configured to receive the fourth control signal;
a first diode coupled to the second terminal of the third switch and a voltage ground;
a second diode coupled to the second terminal of the fourth switch and the voltage ground;
a capacitor coupled between the second terminal of the first switch and the first terminal of the fourth switch; and
a feedback circuit coupled to both terminals of the capacitor, the boost level controller and the PWM modulator, and configured to stabilize the first modulated signal and the second modulated signal.

### Claim 9 (depends on 8)

The boost class-D amplifier of claim 8 further comprising a speaker coupled between the second terminal of the first switch and the first terminal of the fourth switch.

### Claim 10 (depends on 8)

The boost class-D amplifier of claim 8, wherein the first switch, the second switch, the third switch, and the fourth switch are bipolar junction transistors.

### Claim 11 (depends on 8)

The boost class-D amplifier of claim 8, wherein the first switch, the second switch, the third switch, and the fourth switch are metal oxide semiconductor field effect transistor (MOSFET).

### Claim 12 (depends on 8)

The boost class-D amplifier of claim 8, wherein the first control signal and the second control signal are complementary.

### Claim 13 (depends on 12)

The boost class-D amplifier of claim 12 wherein when the first control signal has a high voltage, the second control signal has a low voltage, the third control signal has a high frequency PWM signal and the fourth control signal has a high voltage.

### Claim 14 (depends on 12)

The boost class-D amplifier of claim 12 wherein when the first control signal has a low voltage, the second control signal has a high voltage, the third control signal has a high voltage and the fourth control signal has the high frequency PWM signal.