# US 2009/0267656 A1 · Precision triangle waveform generator

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2009/0267656 A1
- Document ID: US20090267656A1
- Status: Published application
- Kind: A1
- Application number: 12/499,017
- Filed: 2009-07-07
- Published: 2009-10-29
- Earliest claimed: 2005-10-17
- Assignees: Harman International Industries, Incorporated
- Inventors: Gerald R. Stanley
- Web page: https://patentgrep.com/patent/US20090267656A1

## CPC

- H03F 3/217: Class D power amplifiers; Switching amplifiers
- H03K 4/06: having triangular shape
- H03K 7/08: Duration or width modulation {; Duty cycle modulation}
- H03F 2200/03: the amplifier being designed for audio applications
- H03F 2200/351: Pulse width modulation being used in an amplifying circuit
- H03F 2200/78: A comparator being used in a controlling circuit of an amplifier
- H03F: AMPLIFIERS
- 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 triangle waveform generator is set forth that comprises a capacitive element, a regulator, and a control circuit. The regulator is configured to charge the capacitive element in responsive to a first control signal and to discharge the capacitive element in response to a second control signal. The control circuit is responsive to a reference waveform to generate the first and second control signals. In one example, the control circuit generates the first and second control signals in response to the amplitude, frequency, phase, and symmetry of the reference waveform.

## Claims

### Claim at position 1

1-10. (canceled)

### Claim 11

A waveform generator comprising:
a reference waveform generator providing first and second reference signals;
a triangle waveform generator generating a first triangle waveform signal by tracking the frequency and phase of the first reference signal, and generating a second triangle waveform signal by tracking the frequency and phase of the second reference signal.

### Claim 12 (depends on 11)

The waveform generator of claim 11, where the reference waveform generator is operable in a master mode in which the first and second reference signals are generated in response to a fixed clock signal generated internal to the reference waveform generator and a slave mode in which the first and second reference signals are generated in response to an externally generated clock signal.

### Claim 13 (depends on 11)

The waveform generator of claim 11, where the reference waveform generator comprises:
a phase/frequency register adapted to receive data corresponding to the frequency and phase of each of the first and second reference signals; and
a counter responsive to a clock signal and data in the phase/frequency register to generate one or more control signals used in the generation of the first and second reference signals.

### Claim 14 (depends on 11)

The waveform generator of claim 11, where the triangle waveform generator comprises:
a first capacitive element;
a first regulator configured to charge and discharge the first capacitive element, where the first regulator is responsive to a first control signal to charge the first capacitive element and a second control signal to discharge the first capacitive element;
a first control circuit responsive to the first reference signal to generate the first and second control signals;
a second capacitive element;
a second regulator configured to charge and discharge the second capacitive element, where the second regulator is responsive to a third control signal to charge the second capacitive element and a fourth control signal to discharge the second capacitive element; and
a second control circuit responsive to the second reference signal to generate the first and second control signals.

### Claim 15 (depends on 14)

The waveform generator of claim 14, where the first control circuit generates the first and second control signals in response to the frequency and phase of the first reference signal.

### Claim 16 (depends on 15)

The waveform generator of claim 15, where the first control circuit comprises:
a first set of charge pumps adapted to generate the first control signal; and
a second set of charge pumps adapted to generate the second control signal, where the first and second set of charge pumps are cross-coupled with one another to generate the first and second control signals.

### Claim 17 (depends on 15)

The waveform generator of claim 15, where the first control circuit comprises:
a window detection circuit generating a window comparator signal in response to the first triangle waveform;
a first phase frequency detector generating an output signal in response to the window comparator signal and the first reference waveform; and
a second phase frequency detector generating an output signal in response to an inverted version of the window comparator signal and an inverted version of the first reference waveform.

### Claim 18 (depends on 16)

The waveform generator of claim 16, where the first control circuit further comprises:
a first set of charge pumps adapted to generate the first control signal; and
a second set of charge pumps adapted to generate the second control signal.

### Claim 19 (depends on 18)

The triangle waveform generator of claim 18, where the first and second sets of charge pumps are cross-coupled with one another to generate the first and second control signals.

### Claim 20 (depends on 19)

The waveform generator of claim 19, where the first set of charge pumps comprises:
a main charge pump responsive to the output signal of the first phase frequency detector and an inverted version of the output signal of the first phase frequency detector, where the main charge pump provides a switched current Ir for use in generating the first control signal; and
a secondary charge pump responsive to the output signal of the second phase frequency detector and an inverted version of the output signal of the second phase frequency detector, where the secondary charge pump provides a switched current K*Ir for use in generating the first control signal.

### Claim 21 (depends on 20)

The triangle waveform generator of claim 20, where the second set of charge pumps comprises:
a further main charge pump responsive to the output signal of the second phase frequency detector and an inverted version of the output signal of the second phase frequency detector, where the further main charge pump provides a switched current Ir for use in generating the second control signal; and
a further secondary charge pump responsive to the output signal of the first phase frequency detector and an inverted version of the output signal of the first phase frequency detector, where the secondary charge pump provides a switched current K*Ir for use in generating the second control signal.

### Claim 22 (depends on 17)

The waveform generator of claim 17, where the window detection circuit comprises:
a first comparator disposed to compare the first triangle waveform with an upper threshold voltage to generate a corresponding output signal;
a second comparator disposed to compare the first triangle waveform with a lower threshold voltage to generate a corresponding output signal; and
a flip-flop responsive to the output signals of the first and second comparators to generate the window comparator signal.

### Claim 23 (depends on 22)

The waveform generator of claim 22, where the flip-flop is further responsive to the output signals of the first and second comparators to generate the inverted version of the window comparator signal.

### Claim 24

An amplifier comprising:
a power stage;
a reference waveform generator providing first and second reference signals having different phases;
a triangle waveform generator generating a first triangle waveform signal by tracking the amplitude, frequency, and phase of the first reference signal, and generating a second triangle waveform signal by tracking the amplitude, frequency, and phase of the second reference signal;
an interleaved PWM amplifier generating interleaved PWM pulses in response to an input signal and the first and second triangle waveform signals to drive the power stage.

### Claim at position 16

25-34. (canceled)