# US 8,786,316 B2 · Comparator with self-limiting positive feedback

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

- Number: US 8,786,316 B2
- Document ID: US8786316B2
- Status: Granted
- Kind: B2
- Application number: 13/933,499
- Filed: 2013-07-02
- Published: 2013-11-07
- Granted: 2014-07-22
- Earliest claimed: 2009-07-02
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Robert Wolf; Christoph Lang; Xinyu Xing; Sam Kavusi
- Web page: https://patentgrep.com/patent/US8786316B2

## CPC

- H03F 1/38: Positive-feedback circuit arrangements without negative feedback
- H03K 5/08: by limiting; by thresholding; by slicing, i.e. combined limiting and thresholding (H03K5/07 takes precedence; comparing one pulse with another H03K5/22; providing a determined threshold for switching H03K17/30)
- H03K 5/2481: {with at least one differential stage}
- 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 method and circuit for attenuating positive feedback in a comparator in one embodiment includes an amplifier configured to compare a first input signal with a second input signal and to provide an output based upon the comparison, a non-linear function with a first input operably connected to an output of the amplifier, and a feedback loop operably connected to the output of the non-linear function and to a second input of the non-linear function, the feedback loop including a feedback limiting circuit configured to attenuate a feedback signal to the second input of the non-linear function.

## Claims

### Claim 1

A comparator circuit comprising:
an amplifier configured to compare a first input signal with a second input signal and to provide an output signal at an output of the amplifier based upon the comparison;
a positive feedback circuit operatively connected to the output of the amplifier and configured to generate a positive feedback signal, the positive feedback circuit including a MOSFET with a gate operatively connected to the output of the amplifier, the MOSFET being configured to generate the positive feedback signal; and
a capacitor in direct electrical communication with either a source of the MOSFET, which is not directly electrically connected to electrical ground, or between a drain of the MOSFET and electrical ground, the capacitor attenuating the positive feedback signal generated by the MOSFET.

### Claim 2 (depends on 1)

The comparator circuit of claim 1, wherein the capacitor is directly electrically connected between the drain of the MOSFET and electrical ground.

### Claim 3 (depends on 1)

The comparator circuit of claim 1, wherein the capacitor is connected to the source of the MOSFET, which is not directly electrically connected to electrical ground.

### Claim 4 (depends on 1)

The comparator circuit of claim 1, the positive feedback circuit further comprises:
a switch in parallel with the capacitor, the switch being configured to discharge the capacitor selectively to attenuate the positive feedback signal generated by the MOSFET.

### Claim 5 (depends on 1)

The comparator circuit of claim 1, the positive feedback circuit further comprises:
a current source in parallel with the capacitor, the current source being configured to discharge the capacitor selectively to attenuate the positive feedback signal generated by the MOSFET.