CURRENT SENSING MODULE AND POWER CONVERSION APPARATUS AND ELECTRONIC APPARATUS USING THE SAME

• US 20160344290A1
• Filed: 08/19/2015
• Published: 11/24/2016
• Est. Priority Date: 05/22/2015
• Status: Active Grant

• Current Assignee: Midastek Microelectronic Inc.
• Original Assignee: Midastek Microelectronic Inc.
• Inventors: Chua, Well-Chen, Chien, Mao-Chuan, Lin, Chi-Chien, Yang, Muh-Rong
• Granted Patent: US 9,618,540 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 15/146 Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop if no voltage isolation is involved G01R1/203 or G01R19/0092
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 19/2509 Details concerning sampling, digitizing or waveform capturing
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence

Abstract

A current sensing module and a power conversion apparatus and an electronic apparatus using the same are provided. The current sensing module is suitable for detecting a first load current flowing through a first load. The current sensing module includes a sampling stage circuit and an output stage circuit. The sampling stage circuit couples across the first load and selectively exchanges coupling nodes between the sampling stage circuit and the first load by a multiplex switching means, so as to sample the first load current flowing along a first direction or a second direction, and thus generate a sampling signal. The output stage circuit is coupled to the sampling stage circuit and switches coupling nodes between the output stage circuit and the output terminal of the sampling stage circuit, so as to generate a current indication signal indicating the magnitude of the first load current according to the sampling signal.

Claims

1. A current sensing module, adapted to detect a first load current flowing through a first load, the current sensing module comprising:

a sampling stage circuit, coupled across the first load, and configured to selectively exchange coupling nodes between the sampling stage circuit and the first load by applying a multiplex switching means according to a current direction of the first load current, so as to sample the first load current flowing along a first direction or a second direction, and thus generate a sampling signal; and

an output stage circuit, coupled to the sampling stage circuit, and switching coupling nodes between the output stage circuit and an output terminals of the sampling stage circuit in collaboration with a switching timing of the sampling stage circuit, so as to generate a current indication signal for indicating a magnitude of the first load current according to the sampling signal.

2. The current sensing module as claimed in claim 1, wherein the sampling stage circuit comprises:

a first multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the first multiplexer is coupled to a first terminal of the first load, and a second input terminal in the input terminals of the first multiplexer is coupled to a second terminal of the first load, wherein the first multiplexer is controlled by a multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a first input signal;

a second multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the second multiplexer is coupled to the second terminal of the first load, and a second input terminal in the input terminals of the second multiplexer is coupled to the first terminal of the first load, wherein the second multiplexer is controlled by the multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a second input signal; and

a first amplifier, coupled to the output terminals of the first and the second multiplexers for receiving the first and the second input signals, and accordingly generating the sampling signal.

3. The current sensing module as claimed in claim 2, wherein when the current direction of the first load current is the first direction, the first multiplexer is controlled by the multiplexing signal to select the signal received by the first input terminal thereof to serve as the first input signal, and the second multiplexer is controlled by the multiplexing signal to select the signal received by the first input terminal thereof to serve as the second input signal.

4. The current sensing module as claimed in claim 3, wherein when the current direction of the first load current is the second direction opposite to the first direction, the first multiplexer is controlled by the multiplexing signal to select the signal received by the second input terminal thereof to serve as the first input signal, and the second multiplexer is controlled by the multiplexing signal to select the signal received by the second input terminal thereof to serve as the second input signal.

5. The current sensing module as claimed in claim 2, wherein the output stage circuit comprises:

a third multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the third multiplexer is coupled to a first output terminal of the first amplifier, and a second input terminal in the input terminals of the third multiplexer is coupled to a second output terminal of the first amplifier, wherein the third multiplexer is controlled by the multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a third input signal;

a fourth multiplexer, having a plurality of input terminals and an output terminal, wherein the fourth multiplexer is controlled by the multiplexing signal to select coupling one of a first input terminal and a second input terminal in the input terminals of the fourth multiplexer to the output terminal thereof;

a second amplifier, coupled to the output terminals of the third and the fourth multiplexers for receiving the third input signal, and accordingly generating the current indication signal;

a first voltage-dividing unit, coupled between the first input terminal of the fourth multiplexer and a first output terminal of the second amplifier; and

a second voltage-dividing unit, coupled between the second input terminal of the fourth multiplexer and a second output terminal of the second amplifier.

6. The current sensing module as claimed in claim 2, further adapted to detect a second load current flowing through a second load, wherein a third input terminal in the input terminals of the first multiplexer is coupled to a first terminal of the second load, and a third input terminal in the input terminals of the second multiplexer is coupled to a second terminal of the second load.

7. The current sensing module as claimed in claim 6, wherein the first and the second multiplexers select to couple the two terminals of the first load for detecting the first load current during a first detection period, and select to couple the two terminals of the second load for detecting the second load current during a second detection period.

8. A power conversion apparatus, comprising:

a power conversion circuit, configured to convert an external power or a battery power into a working power for providing to a load apparatus, wherein the power conversion circuit has a first detection resistor coupled in series on a power conversion path;

a current sensing module, coupled across the first detection resistor for detecting a first load current flowing through the first detection resistor, wherein the current sensing module comprises;

a sampling stage circuit, coupled across the first detection resistor, and configured to selectively exchange coupling nodes between the sampling stage circuit and the first load by applying a multiplex switching means according to a current direction of the first load current, so as to sample the first load current flowing along a first direction or a second direction, and thus generate a sampling signal; and

an output stage circuit, coupled to the sampling stage circuit, and switching coupling nodes between the output stage circuit and output terminals of the sampling stage circuit in collaboration with a switching timing of the sampling stage circuit, so as to generate a current indication signal indicating a magnitude of the first load current according to the sampling signal; and

a control circuit, coupled to the power conversion circuit and the current sensing module, and configured to control operations of the power conversion circuit and the current sensing module.

9. The power conversion apparatus as claimed in claim 8, wherein the sampling stage circuit comprises:

a first multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the first multiplexer is coupled to a first terminal of the first detection resistor, and a second input terminal in the input terminals of the first multiplexer is coupled to a second terminal of the first detection resistor, wherein the first multiplexer is controlled by a multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a first input signal;

a second multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the second multiplexer is coupled to the second terminal of the first detection resistor, and a second input terminal in the input terminals of the second multiplexer is coupled to the first terminal of the first detection resistor, wherein the second multiplexer is controlled by the multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a second input signal; and

a first amplifier, coupled to the output terminals of the first and the second multiplexers for receiving the first and the second input signals, and accordingly generating the sampling signal.

10. The power conversion apparatus as claimed in claim 9, wherein when the power conversion circuit operates in a boost mode, the power conversion circuit converts the battery power into the working power, the first multiplexer is controlled by the multiplexing signal to select the signal received by the first input terminal thereof to serve as the first input signal, and the second multiplexer is controlled by the multiplexing signal to select the signal received by the first input terminal thereof to serve as the second input signal.

11. The power conversion apparatus as claimed in claim 10, wherein when the power conversion circuit operates in a buck mode, the power conversion circuit converts the external power into the working power, the first multiplexer is controlled by the multiplexing signal to select the signal received by the second input terminal thereof to serve as the first input signal, and the second multiplexer is controlled by the multiplexing signal to select the signal received by the second input terminal thereof to serve as the second input signal.

12. The power conversion apparatus as claimed in claim 9, wherein the output stage circuit comprises:

a third multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the third multiplexer is coupled to a first output terminal of the first amplifier, and a second input terminal in the input terminals of the third multiplexer is coupled to a second output terminal of the first amplifier, wherein the third multiplexer is controlled by the multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a third input signal;

a fourth multiplexer, having a plurality of input terminals and an output terminal, wherein the fourth multiplexer is controlled by the multiplexing signal to select coupling one of a first input terminal and a second input terminal in the input terminals of the fourth multiplexer to the output terminal thereof;

a second amplifier, coupled to the output terminals of the third and the fourth multiplexers for receiving the third input signal, and accordingly generating the current indication signal;

a first voltage-dividing unit, coupled between the first input terminal of the fourth multiplexer and a first output terminal of the second amplifier; and

a second voltage-dividing unit, coupled between the second input terminal of the fourth multiplexer and a second output terminal of the second amplifier.

13. The power conversion apparatus as claimed in claim 9, wherein the current sensing module is further adapted to detect a second load current flowing through a second detection resistor, wherein a third input terminal in the input terminals of the first multiplexer is coupled to a first terminal of the second detection resistor, and a third input terminal in the input terminals of the second multiplexer is coupled to a second terminal of the second detection resistor.

14. The power conversion apparatus as claimed in claim 13, wherein the first and the second multiplexers select to couple the two terminals of the first detection resistor for detecting the first load current during a first detection period, and select to couple the two terminals of the second detection resistor for detecting the second load current during a second detection period.

15. An electronic apparatus, comprising:

a battery, configured to provide a battery power;

a charging terminal, configured to receive an external power;

a power conversion apparatus, coupled to the battery and the charging terminal, wherein the power conversion apparatus comprises;

a power conversion circuit, configured to convert the external power or the battery power into a working power, wherein the power conversion circuit has a first detection resistor connected in series on a power conversion path;

a current sensing module, coupled across the first detection resistor for detecting a first load current flowing through the first detection resistor, wherein the current sensing module comprises;

a sampling stage circuit, coupled across the first detection resistor, and configured to selectively exchange coupling nodes between the sampling stage circuit and the first load by applying a multiplex switching means according to a current direction of the first load current, so as to sample the first load current flowing along a first direction or a second direction, and thus generate a sampling signal; and

an output stage circuit, coupled to the sampling stage circuit, and switching coupling nodes between the output stage circuit and output terminals of the sampling stage circuit in collaboration with a switching timing of the sampling stage circuit, so as to generate a current indication signal indicating a magnitude of the first load current according to the sampling signal; and

the control circuit, coupled to the power conversion circuit and the current sensing module, and configured to control operations of the power conversion circuit and the current sensing module.

16. The electronic apparatus as claimed in claim 15, further comprising:

a load apparatus, coupled to the power conversion apparatus, and operating based on a working power provided by the power conversion apparatus.

17. The electronic apparatus as claimed in claim 15, wherein the sampling stage circuit comprises:

a first multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the first multiplexer is coupled to a first terminal of the first detection resistor, and a second input terminal in the input terminals of the first multiplexer is coupled to a second terminal of the first detection resistor, wherein the first multiplexer is controlled by a multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a first input signal;

a second multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the second multiplexer is coupled to the second terminal of the first detection resistor, and a second input terminal in the input terminals of the second multiplexer is coupled to the first terminal of the first detection resistor, wherein the second multiplexer is controlled by the multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a second input signal; and

a first amplifier, coupled to the output terminals of the first and the second multiplexers for receiving the first and the second input signals, and accordingly generating the sampling signal.

18. The electronic apparatus as claimed in claim 17, wherein the control circuit further determines whether the external power is connected to the electronic apparatus through the charging terminal, and when the control circuit determines that the external power is not connected to the electronic apparatus, the control circuit controls the power conversion circuit to operate in a boost mode, and when the control circuit determines that the external power is connected to the electronic apparatus, the control circuit controls the power conversion circuit to operate in a buck mode.

19. The electronic apparatus as claimed in claim 18, wherein when the power conversion circuit operates in the boost mode, the power conversion circuit converts the battery power into the working power, the first multiplexer is controlled by the multiplexing signal to select the signal received by the first input terminal thereof to serve as the first input signal, and the second multiplexer is controlled by the multiplexing signal to select the signal received by the first input terminal thereof to serve as the second input signal.

20. The electronic apparatus as claimed in claim 19, wherein when the power conversion circuit operates in the buck mode, the power conversion circuit converts the external power into the working power, the first multiplexer is controlled by the multiplexing signal to select the signal received by the second input terminal thereof to serve as the first input signal, and the second multiplexer is controlled by the multiplexing signal to select the signal received by the second input terminal thereof to serve as the second input signal.

21. The electronic apparatus as claimed in claim 17, wherein the output stage circuit comprises:

a third multiplexer, having a plurality of input terminals and an output terminal, wherein a first input terminal in the input terminals of the third multiplexer is coupled to a first output terminal of the first amplifier, and a second input terminal in the input terminals of the third multiplexer is coupled to a second output terminal of the first amplifier, wherein the third multiplexer is controlled by the multiplexing signal to select a signal received by one of the first input terminal and the second input terminal thereof to serve as a third input signal;

a fourth multiplexer, having a plurality of input terminals and an output terminal, wherein the fourth multiplexer is controlled by the multiplexing signal to select coupling one of a first input terminal and a second input terminal in the input terminals to the output terminal thereof;

a second amplifier, coupled to the output terminals of the third and the fourth multiplexers for receiving the third input signal, and accordingly generating the current indication signal;

a first voltage-dividing unit, coupled between the first input terminal of the fourth multiplexer and a first output terminal of the second amplifier; and

a second voltage-dividing unit, coupled between the second input terminal of the fourth multiplexer and a second output terminal of the second amplifier.

22. The electronic apparatus as claimed in claim 17, further comprising a second detection resistor dispose din the electronic apparatus, wherein the current sensing module is further adapted to detect a second load current flowing through the second detection resistor, a third input terminal in the input terminals of the first multiplexer is coupled to a first terminal of the second detection resistor, and a third input terminal in the input terminals of the second multiplexer is coupled to a second terminal of the second detection resistor.

23. The electronic apparatus as claimed in claim 22, wherein the first and the second multiplexers select to couple the two terminals of the first detection resistor for detecting the first load current during a first detection period, and select to couple the two terminals of the second detection resistor for detecting the second load current during a second detection period.