# US 12,113,445 B2 · Method and apparatus for sensing the input voltage of a power converter

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- Number: US 12,113,445 B2
- Document ID: US12113445B2
- Status: Granted
- Kind: B2
- Application number: 18/371,332
- Filed: 2023-09-21
- Published: 2024-07-25
- Granted: 2024-10-08
- Earliest claimed: 2020-11-16
- Assignees: Semiconductor Components Industries, LLC
- Applicants: Semiconductor Components Industries, LLC
- Inventors: Anders Lind
- Web page: https://patentgrep.com/patent/US12113445B2

## CPC

- H02M 3/1588: {comprising at least one synchronous rectifier element (H02M3/1582, H02M3/1584 take precedence)}
- H02M 1/0009: {Devices or circuits for detecting current in a converter}
- H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M 1/083: {for the ignition at the zero crossing of the voltage or the current}
- H02M 1/14: Arrangements for reducing ripples from DC input or output
- H02M 1/32: Means for protecting converters other than automatic disconnection
- H02M 1/42: Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M 1/4225: {using a non-isolated boost converter}
- H02M 3/1586: {switched with a phase shift, i.e. interleaved}
- H02M 7/219: in a bridge configuration
- H02M 1/4233: {using a bridge converter comprising active switches}
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- 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)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A method of detecting zero crossings in an AC input voltage at an input of a power converter includes measuring, at a first time, a first voltage. If the first voltage is positive: determining that the first time corresponds to a positive half-cycle of the AC input voltage. If the first voltage is equal to zero: a) determining that the first time corresponds to a negative half-cycle of the AC input voltage; b) turning on a high-side switch of the power converter for a first time period; and c) measuring, during the first time period, a second voltage. If the second voltage is less than a first threshold, turning off the high-side switch and repeating b) and c) after a time delay. If the second voltage is less than a second threshold, maintaining the high-side switch in an ON state for a second time period.

## Claims

### Claim 1

A method of detecting zero crossings in an AC input voltage at an input of a power converter, the method comprising:
measuring, at a first time, a first voltage at the input of the power converter;
if the first voltage is positive:
determining that the first time corresponds to a positive half-cycle of the AC input voltage; and
if the first voltage is equal to approximately zero:
a) determining that the first time corresponds to a negative half-cycle of the AC input voltage;
b) turning on a high-side switch of the power converter for a first time period; and
c) measuring, during the first time period, a second voltage at the input of the power converter;
if the second voltage is less than a first threshold, turning off the high-side switch and repeating b) and c) after a time delay; and
if the second voltage is less than a second threshold, maintaining the high-side switch in an ON state for a second time period.

### Claim 2 (depends on 1)

The method of claim 1 wherein the first threshold corresponds to a forward voltage drop of a diode corresponding to a low-side switch.

### Claim 3 (depends on 1)

The method of claim 1 wherein the first threshold is on the order of 3 V.

### Claim 4 (depends on 1)

The method of claim 1 wherein the second threshold is a negative value.

### Claim 5 (depends on 1)

The method of claim 1 wherein the second time period is longer than the first time period.

### Claim 6 (depends on 1)

The method of claim 1 wherein the first time period is chosen so that the AC input voltage at the input of the power converter is able to be sampled.

### Claim 7 (depends on 1)

The method of claim 1 further comprising turning on a low-side switch during the positive half-cycle.

### Claim 8 (depends on 7)

The method of claim 7 wherein the low-side switch and the high-side switch are operated as mutually exclusive switches.

### Claim 9 (depends on 1)

The method of claim 1 further comprising, prior to turning on the high-side switch, measuring a DC bus voltage.

### Claim 10 (depends on 9)

The method of claim 9 wherein, measuring the second voltage comprises computing a third voltage equal to the second voltage minus the DC bus voltage.

### Claim 11

A method of forming guard bands at zero crossings of an AC input signal, the method comprising:
turning on a low-side switch;
measuring a first voltage corresponding to the AC input signal;
determining that the first voltage is less than or equal to a first threshold;
turning off the low-side switch;
waiting a predetermined time;
turning on a high-side switch for a first time period;
measuring a second voltage corresponding to the AC input signal;
computing a third voltage using the second voltage;
determining that the third voltage is less than a second threshold;
turning on the high-side switch for a second time period;
measuring a fourth voltage corresponding to the AC input signal;
computing a fifth voltage using the fourth voltage;
determining that the fifth voltage is greater than a third threshold;
turning off the high-side switch; and
turning on the low-side switch.

### Claim 12 (depends on 11)

The method of claim 11 wherein the first threshold corresponds to a forward voltage drop of a diode corresponding to the low-side switch.

### Claim 13 (depends on 11)

The method of claim 11 further comprising measuring a DC bus voltage, wherein computing the third voltage comprises subtracting the DC bus voltage from the second voltage.

### Claim 14 (depends on 11)

The method of claim 11 wherein the second threshold is a negative value.

### Claim 15 (depends on 11)

The method of claim 11 wherein the third threshold is a negative value.

### Claim 16 (depends on 11)

The method of claim 11 further comprising waiting a second predetermined time before turning on the low-side switch.

### Claim 17 (depends on 11)

The method of claim 11 further comprising:
measuring a sixth voltage corresponding to the AC input signal; and
determining that the sixth voltage is greater than zero before turning on the low-side switch.

### Claim 18 (depends on 17)

The method of claim 17 wherein the sixth voltage is greater than a forward voltage drop of a diode corresponding to the low-side switch.

### Claim 19

A method of detecting a positive to negative crossing in an AC input signal, the method comprising:
measuring a first voltage corresponding to the AC input signal;
determining that the first voltage is less than or equal to a first threshold;
turning off a low-side switch;
measuring a second voltage corresponding to the AC input signal, wherein the second voltage is measured through a diode of the low-side switch;
determining that the second voltage is less than or equal to a second threshold;
waiting a first time period;
turning on a high-side switch for a second time period;
measuring, during the second time period, a third voltage corresponding to the AC input signal;
if the third voltage is less than a third threshold, turning off the high-side switch and repeating the steps of turning on the high-side switch and measuring the third voltage after a third time period; and
if the third voltage is less than a fourth threshold, maintaining the high-side switch in an ON state for a remainder of the AC half-cycle.

### Claim 20 (depends on 19)

The method of claim 19, wherein
the first threshold is approximately 3 V;
the second threshold is approximately 0 V; and
the fourth threshold is a negative value.