Charging device and safety function control circuit and method thereof

Patent metadata

Field	Value
Publication number	US-12224659-B2
Application number	US-202318102784-A
Country	US
Kind code	B2
Filing date	Jan 30, 2023
Priority date	Feb 11, 2022
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

A charging device and a safety function control circuit and method thereof are provided. When a charging device is not connected to a load, a converted voltage value of a power connection terminal of the charging device is kept to be lower than a safe voltage value so as to maintain a safe mode. The safety function control circuit includes a first control module and a second control module for constant voltage control. The first control module and the second control module perform matching control on a power conversion circuit of the charging device, and in case of a single fault of one of the control modules, the other module is still capable of keeping the converted voltage value to be less than the safe voltage value. Thus, it is ensured that the safe mode stays functional in case of a concurrency of both a single hardware fault and a single firmware fault.

First claim

What is claimed is:

1. A safety function control circuit for a charging device, the charging device comprising a power conversion circuit, a power connection terminal, a switch circuit coupled between the power connection terminal and the power conversion circuit, and a first control module coupled to the switch circuit, the power connection terminal and the power conversion circuit; a voltage detection section being defined between the switch circuit and the power conversion circuit, the first control module operating in a safe mode when the power connection terminal is not connected to a load; the safety function control circuit comprising:
a first constant voltage control zone, configured at the first control module, and coupled to a feedback control module of the power conversion circuit via a first control terminal of the first control module, wherein in the safe mode, the first control module generates, based on a comparison between a first predetermined voltage value and a first detection voltage value obtained from the voltage detection section, a first control signal used for a converted voltage value of the power conversion circuit to be lower than a safe voltage value; and
a second constant voltage control zone, comprising a second control module coupled to the power connection terminal, a second control terminal of the second control module being coupled to the feedback control module of the power conversion circuit, wherein in the safe mode, the second control module generates, based on a comparison between a second predetermined voltage value and a second detection voltage value obtained from the voltage detection section, a second control signal used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value;
wherein in the safe mode, when the first control signal is not used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value, the feedback control module is controlled by the second control signal, and
wherein in the safe mode, when the second control signal is not used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value, the feedback control module is controlled by the first control signal.

2. The safety function control circuit of claim 1 , wherein the feedback control module further comprises:
an optocoupler;
wherein in the safe mode, a path is formed between the optocoupler and a control terminal corresponding to the first control signal or the second control signal having a level lower than a voltage level, so that the power conversion circuit is controlled by the corresponding first or second control module.

3. The safety function control circuit of claim 2 , wherein in the safe mode, the first control signal has a first low voltage level, the second control signal has a second low voltage level, the second low voltage level is higher than the first low voltage level, and the path is formed between the optocoupler and the first control terminal having the first low voltage level.

4. The safety function control circuit of claim 1 , wherein the feedback control module further comprises:
a logical unit, arranged between the first control terminal and the second control terminal, the logical unit configured to transmit the first control signal or the second control signal.

5. A charging device, comprising:
a power conversion circuit, comprising a feedback control module;
a switch circuit, coupled to the power conversion circuit, a voltage detection section being defined between the switch circuit and the power conversion circuit;
a power connection terminal, coupled to the switch circuit and configured to connect to a load;
a first control module, coupled to the switch circuit, the power connection terminal, the voltage detection section and the feedback control module, the first control module operating in a safe mode when the power connection terminal is not connected to the load, and a first control terminal of the first control module being coupled to the feedback control module, and in the safe mode, the first control module generating, based on a comparison between a first predetermined voltage value and a first detection voltage value obtained from the voltage detection section, a first control signal used for a converted voltage value of the power conversion circuit to be lower than a safe voltage value; and
a second control module, coupled to the power connection terminal, the voltage detection section and the feedback control module, and a second control terminal of the second control module being coupled to the feedback control module, the second control module generating, based on a comparison between a second predetermined voltage value and a second detection voltage value obtained from the voltage detection section, a second control signal used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value;
wherein in the safe mode, when the first control signal is not used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value, the feedback control module is controlled by the second control signal, and
wherein in the safe mode, when the second control signal is not used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value, the feedback control module is controlled by the first control signal.

6. The charging device of claim 5 , wherein the feedback control module further comprises:
an optocoupler;
wherein in the safe mode, a path is formed between the optocoupler and a control terminal corresponding to the first control signal or the second control signal, so that the power conversion circuit is controlled by the corresponding first or second control module.

7. The charging device of claim 6 , wherein the first control signal used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value has a first low voltage level, the second control signal used for the converted voltage value of the power conversion circuit to be lower than the safe voltage value has a second low voltage level, the second low voltage level is higher than the first low voltage level, and the path is formed between the optocoupler and the first control terminal having the first low voltage level.

8. The charging device of claim 5 , wherein the feedback control module further comprises:
a logical unit, arranged between the first control terminal and the second control terminal, the logical unit configured to transmit the first control signal or the second control signal.

9. A safety function control method for a charging device, applied to have a converted voltage value of a power connection terminal of the charging device be lower than a safe voltage value so as to achieve an operation in a safe mode when the charging device is not connected to a load, the method comprising:
a first constant voltage control step, comprising comparing a first detection voltage value on a power line of a power conversion circuit in the charging device with a first predetermined voltage value, and generating a first control signal for controlling the power conversion circuit;
a second constant voltage control step, performed only in the safe mode, comparing a second detection voltage value on the power line with a second predetermined voltage value, and generating a second control signal for controlling the power conversion circuit; and
a determination step, transmitting the first control signal or the second control signal to a power conversion circuit, so that the converted voltage value of the charging device stays

Assignees

• Fsp Tech Inc

Inventors

• Lin Che-Min
• Chan Kuo-Chieh
• Lee Kuan-Jung
• Lien Chi-Chang
• Chu Ching-Chia

Classifications

• H02J7/64 Primary

  against overvoltage · CPC title

• H02J7/933

  the cycle being controlled or terminated in response to electric parameters · CPC title

• H02M3/33523

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title

• H02J2207/20

  Charging or discharging characterised by the power electronics converter · CPC title

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title