# US 2018/0026642 A1 · Feedback control systems with pulse density signal processing capabilities

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- Number: US 2018/0026642 A1
- Document ID: US20180026642A1
- Status: Published application
- Kind: A1
- Application number: 15/214,310
- Filed: 2016-07-19
- Published: 2018-01-25
- Earliest claimed: 2016-07-19
- Assignees: Altera Corporation
- Applicants: Altera Corporation
- Inventors: Benjamin Peter Jeppesen
- Web page: https://patentgrep.com/patent/US20180026642A1

## CPC

- H03K 19/17708: {using an AND matrix followed by an OR matrix, i.e. programmable logic arrays}
- H03K 19/00346: {Modifications for eliminating interference or parasitic voltages or currents}
- H03K 19/1778: Structural details for adapting physical parameters
- H03K 19/21: EXCLUSIVE-OR circuits, i.e. giving output if input signal exists at only one input; COINCIDENCE circuits, i.e. giving output only if all input signals are identical
- H04B 14/026: {using pulse time characteristics modulation, e.g. width, position, interval}
- H04B 14/06: using differential modulation, e.g. delta modulation
- 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)
- H04B: TRANSMISSION

## Abstract

A feedback control system may include a feedback controller for controlling a plant using pulse density signals. The feedback controller may include a pulse density signal generator and a controller logic circuit. The pulse density signal generator may receive input command signals and generate signed or unsigned pulse density input signals. The controller logic may receive the pulse density input signals from the pulse density signal generator and feedback pulse density signals from the plant and may generate corresponding pulse density control signals for controlling the plant based on the input command signals. The controller logic may include a sign change logic, an addition circuit, and an optional amplifier circuit. The pulse density signal generator may also include rate transition circuits for ensuring that the pulse density input signals and the feedback pulse density signals are uncorrelated.

## Claims

### Claim 1

A feedback control system, comprising:
a dynamic subsystem under control; and
a feedback controller that controls the dynamic subsystem under control and that receives feedback signals from the dynamic subsystem under control, wherein the dynamic subsystem under control receives pulse density control signals from the feedback controller.

### Claim 2 (depends on 1)

The feedback control system of claim 1, wherein the feedback controller comprises an integrated circuit die.

### Claim 3 (depends on 1)

The feedback control system of claim 1, wherein the feedback controller includes a pulse density signal generator that outputs pulse density input signals.

### Claim 4 (depends on 3)

The feedback control system of claim 3, wherein the pulse density signal generator comprises a data converter.

### Claim 5 (depends on 4)

The feedback control system of claim 4, wherein the data converter comprises a sigma-delta converter.

### Claim 6 (depends on 3)

The feedback control system of claim 3, wherein the feedback controller further includes a controller logic circuit that receives the pulse density input signals from the pulse density signal generator and the feedback signals from the dynamic subsystem under control.

### Claim 7 (depends on 6)

The feedback control system of claim 6, wherein the controller logic circuit comprises:
an addition logic circuit; and
a sign change logic circuit.

### Claim 8 (depends on 7)

The feedback control system of claim 7, wherein the addition logic circuit performs a summing function using logic OR gates.

### Claim 9 (depends on 7)

The feedback control system of claim 7, wherein the addition logic circuit performs a multiply function using logic AND gates.

### Claim 10 (depends on 3)

The feedback control system of claim 3, wherein the feedback controller includes a rate transition circuit that ensures that the pulse density input signals and the feedback signals are uncorrelated.

### Claim 11 (depends on 1)

The feedback control system of claim 1, further comprising:
a sigma-delta analog-to-digital converter that receives analog signals from the dynamic subsystem under control and that outputs the feedback signals to the feedback controller via a feedback path.

### Claim 12

A method for operating a feedback control system, comprising:
with a feedback controller, receiving input command signals;
with the feedback controller, controlling a dynamic subsystem under control based on the input command signals by outputting pulse density control signals, wherein the pulse density control signals are received at the dynamic subsystem under control; and
with the feedback controller, receiving feedback signals from the dynamic subsystem under control.

### Claim 13 (depends on 12)

The method of claim 12, further comprising:
with an analog-to-digital converter, receiving analog signals from the dynamic subsystem under control and outputting the feedback signals to the feedback controller.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
with a pulse density signal generator in the feedback controller, receiving the input command signals and outputting pulse density input signals; and
with a controller logic circuit in the feedback controller, receiving the input command signals from the pulse density signal generator and the feedback signals from the analog-to-digital converter and outputting the pulse density control signals to the dynamic subsystem under control.

### Claim 15

(canceled)

### Claim 16

An integrated circuit die, comprising:
an input that receives an input command signal;
a pulse density signal generator that receives the input command signal and that generates a corresponding pulse density input signal; and
a controller logic that receives the pulse density input signal from the pulse density signal generator, that receives a feedback signal from an external dynamic subsystem under control, and that outputs corresponding a pulse density control signal for controlling the dynamic subsystem under control, wherein the pulse density signal generator includes a rate transition circuit that ensures that the pulse density input signal and the feedback signal are uncorrelated.

### Claim 17 (depends on 16)

The integrated circuit die of claim 16, wherein the controller logic is implemented using reconfigurable logic circuits within the integrated circuit die.

### Claim 18 (depends on 16)

The integrated circuit die of claim 16, wherein the pulse density signal generator comprises a sigma-delta data converter.

### Claim 19 (depends on 16)

The integrated circuit die of claim 16, wherein the pulse density signal generator outputs a signed pulse density input signal.

### Claim 20

(canceled)

### Claim 21 (depends on 3)

The feedback control system of claim 3, wherein the feedback controller is configured to compute a difference between the pulse density input signals and the feedback signals and to amplify the difference by a predetermined gain value.

### Claim 22 (depends on 1)

The feedback control system of claim 1, wherein the pulse density control signals include a sign bit component.