# US 2014/0152339 A1 · Proportional-integral-derivative (pid) analog controller and a method for testing a pid analog controller of a dc/dc converter

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- Number: US 2014/0152339 A1
- Document ID: US20140152339A1
- Status: Published application
- Kind: A1
- Application number: 13/705,508
- Filed: 2012-12-05
- Published: 2014-06-05
- Earliest claimed: 2012-12-05
- Assignees: NXP B.V.
- Applicants: NXP B.V.
- Inventors: RODRIGO ALEXANDER MORA SANCHEZ
- Web page: https://patentgrep.com/patent/US20140152339A1

## CPC

- H02M 3/00: Conversion of DC power input into DC power output
- G01R 31/40: Testing power supplies (testing photovoltaic devices H02S50/10)
- G05F 1/468: {characterised by reference voltage circuitry, e.g. soft start, remote shutdown}
- H02M 1/0003: {Details of control, feedback or regulation circuits}
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES

## Abstract

Embodiments of a method for testing a Proportional-Integral-Derivative (PID) analog controller of a Direct Current (DC)/DC converter and a PID analog controller of a DC/DC converter are described. In one embodiment, a method for testing a PID analog controller of a DC/DC converter involves setting an analog regulation loop, which is formed by an operational transconductance amplifier (OTA) of the PID analog controller and a feedback network of the PID analog controller, to a stable condition and testing a DC parameter of the PID analog controller and setting the analog regulation loop to an unstable condition and testing an Alternate Current (AC) parameter of the PID analog controller. Other embodiments are also described.

## Claims

### Claim 1

A method for testing a Proportional-Integral-Derivative (PID) analog controller of a Direct Current (DC)/DC converter, the method comprising:
setting an analog regulation loop, which is formed by an operational transconductance amplifier (OTA) of the PID analog controller and a feedback network of the PID analog controller, to a stable condition and testing a DC parameter of the PID analog controller; and
setting the analog regulation loop to an unstable condition and testing an Alternate Current (AC) parameter of the PID analog controller.

### Claim 2 (depends on 1)

The method of claim 1, wherein a terminal of the PID analog controller receives an output voltage of the DC-DC converter.

### Claim 3 (depends on 2)

The method of claim 2, wherein setting the analog regulation loop, which is formed by the OTA of the PID analog controller and the feedback network of the PID analog controller, to the stable condition and testing the DC parameter of the PID analog controller includes electrically disconnecting a capacitor that is connected between the terminal of the PID analog controller and a first input terminal of the OTA from the feedback network.

### Claim 4 (depends on 3)

The method of claim 3, wherein setting the analog regulation loop, which is formed by the OTA of the PID analog controller and the feedback network of the PID analog controller, to the stable condition and testing the DC parameter of the PID analog controller further includes electrically connecting an NMOS transistor that operates in saturation to an output terminal of the OTA.

### Claim 5 (depends on 3)

The method of claim 3, wherein setting the analog regulation loop to the unstable condition and testing the AC parameter of the PID analog controller includes electrically connecting the capacitor to the feedback network.

### Claim 6 (depends on 4)

The method of claim 4, wherein setting the analog regulation loop to the unstable condition and testing the AC parameter of the PID analog controller further includes setting the capacitance value of the capacitor such that the phase margin of the PID analog controller becomes negative and the PID analog controller starts to oscillate.

### Claim 7 (depends on 2)

The method of claim 2, wherein setting the analog regulation loop, which is formed by the OTA of the PID analog controller and the feedback network of the PID analog controller, to the stable condition and testing the DC parameter of the PID analog controller includes:
closing a first CMOS switch of the feedback network to electrically connect an NMOS transistor of the feedback network to an output terminal of the OTA; and
opening a second CMOS switch of the feedback network that is connected to a capacitor that is connected between the output terminal of the PID analog controller and a first input terminal of the OTA.

### Claim 8 (depends on 7)

The method of claim 7, wherein closing the first CMOS switch of the feedback network includes setting a pull-down transistor connected to the NMOS transistor to a high-impedance state.

### Claim 9 (depends on 7)

The method of claim 7, wherein setting the analog regulation loop to the unstable condition and testing the AC parameter of the PID analog controller includes closing the second CMOS switch of the feedback network.

### Claim 10 (depends on 9)

The method of claim 9, wherein setting the analog regulation loop to the unstable condition and testing the AC parameter of the PID analog controller further includes setting the capacitance value of the capacitor such that the phase margin of the analog regulation loop becomes negative and the analog regulation loop starts to oscillate.

### Claim 11 (depends on 2)

The method of claim 2, wherein the DC/DC converter is a buck DC/DC converter.

### Claim 12 (depends on 11)

The method of claim 11, wherein the output voltage of the DC/DC converter is smaller than an input voltage of the DC/DC converter.

### Claim 13 (depends on 2)

The method of claim 2, wherein the PID analog controller calculates a difference value between the output voltage of the DC/DC converter and a reference voltage based on proportional, integral and derivative values.

### Claim 14

A Proportional-Integral-Derivative (PID) analog controller of a Direct Current (DC)/DC converter, the PID analog controller comprising:
an operational transconductance amplifier (OTA);
a feedback network connected to a terminal of the PID analog controller at which an output voltage of the DC/DC converter is received and to an output terminal of the OTA, wherein the feedback network comprises a first CMOS switch connected to the output terminal of the OTA, a second CMOS switch, an NMOS transistor connected to the first CMOS switch and to the terminal of the PID analog controller, and a pull-down transistor connected to the first CMOS switch and to the NMOS transistor; and
a capacitor connected to the OTA through the second CMOS switch and to the terminal of PID analog controller.

### Claim 15 (depends on 14)

The PID analog controller of claim 14, further comprising:
an impedance circuit connected to a first input terminal of the OTA and to the output terminal of the OTA;
a first resistor connected to the terminal of the PID analog controller and to the first input terminal of the OTA; and
a second resistor connected to ground and to the first input terminal of the OTA.

### Claim 16 (depends on 14)

The PID analog controller of claim 14, wherein the second CMOS switch is connected to the first input terminal of the OTA, and wherein a second input terminal of the OTA is connected to a reference voltage.

### Claim 17 (depends on 14)

The PID analog controller of claim 14, wherein the PID analog controller is configured to calculate a difference value between the output voltage of the DC/DC converter and to a reference voltage based on proportional, integral and derivative values.

### Claim 18 (depends on 14)

A buck DC/DC converter, wherein the buck DC/DC converter comprises the PID analog controller of claim 14.

### Claim 19

A method for testing a Proportional-Integral-Derivative (PID) analog controller of a buck Direct Current (DC)/DC converter, the method comprising:
setting an analog regulation loop, which is formed by an operational transconductance amplifier (OTA) of the PID analog controller and a feedback network of the PID analog controller, to a stable condition and testing a DC parameter of the PID analog controller, the setting comprising:
closing a first CMOS switch of the feedback network to electrically connect a gate terminal of an NMOS transistor of the feedback network to an output terminal of the OTA; and
opening a second CMOS switch of the feedback network that is connected to a capacitor that is connected between a terminal of the PID analog controller at which an output voltage of the DC/DC converter is received and to a first input terminal of the OTA to electrically disconnect the capacitor from the feedback network, wherein a source terminal of the NMOS transistor is connected to the terminal of the PID analog controller and a drain terminal of the NMOS transistor is connected to a supply voltage; and
setting the analog regulation loop to an unstable condition and testing an Alternate Current (AC) parameter of the PID analog controller, the setting comprising closing the second CMOS switch of the feedback network to electrically connect the capacitor to the feedback network.

### Claim 20 (depends on 19)

The method of claim 19, wherein closing the first CMOS switch of the feedback network further includes setting a pull-down transistor connected to the NMOS transistor to a high-impedance state, wherein setting the analog regulation loop to the unstable condition and testing the AC parameter of the PID analog controller further includes setting the capacitance value of the capacitor such that the phase margin of the analog regulation loop becomes negative and the analog regulation loop starts to oscillate.