Electronic control apparatus for controlling driving of load by MOS FETs

• US 20050046280A1
• Filed: 08/27/2004
• Published: 03/03/2005
• Est. Priority Date: 08/27/2003
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Itabashi, Toru, Kanayama, Mitsuhiro
• Granted Patent: US 7,924,063 B2
• Time in Patent Office: Days
• US Class Current: 307/131
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/162 without feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 17/693 Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors logic circuits H03K19/00; code converters H03M5/00, H03M7/00

Abstract

An ECU has a main IC and at least one auxiliary IC, with at least the auxiliary IC driving one or more MOS FETs to control supplying of power to respective electrical loads, e.g., in a vehicle. A stepped-up voltage, higher than the circuit power source voltage, is generated within the main IC and supplied to each auxiliary IC, for driving gate electrodes of the MOS FETs. Electrical noise produced by operation of a voltage step-up circuit in the main IC is effectively suppressed by elements that are coupled only to a power source terminal of the main IC alone.

Claims

1. An electronic control apparatus comprising:

a main integrated circuit, comprising

a power source terminal coupled to receive an externally supplied power source voltage,

a voltage step-up circuit operating from said power source voltage supplied to said power source terminal to produce a stepped-up voltage that is higher than said power source voltage, and

a stepped-up voltage output terminal coupled to receive said stepped-up voltage; and

at least one auxiliary integrated circuit, comprising

a stepped-up voltage input terminal coupled to receive said stepped-up voltage from said stepped-up voltage output terminal of said main integrated circuit, and

drive circuit means for selectively applying said stepped-up voltage to a gate electrode of a MOS FET (metal-oxide semiconductor field effect transistor) that is connected in a current flow path of an electrical load, to effect on and off switching of said MOS FET.

2. An electronic control apparatus as claimed in claim 1, comprising noise reduction means connected to said power source input terminal of said main integrated circuit.

3. An electronic control apparatus as claimed in claim 2, wherein said noise reduction means comprises at least one element that is externally connected directly to said power source input terminal.

4. An electronic control apparatus as claimed in claim 3, wherein said noise reduction means comprises at least one of an inductor that is connected between a source of said power source voltage and said power source input terminal and a capacitor that is connected between said power source input terminal and a ground potential of said main integrated circuit.

5. An electronic control apparatus as claimed in claim 1, wherein a circuit path conveying said power source voltage within said electronic control apparatus is branched to form a first circuit path connected to said power source input terminal of said main integrated circuit and a second circuit path constituting a current flow path of said electrical load, and wherein said electronic control apparatus comprises noise reduction means connected within said first circuit path.

6. An electronic control apparatus as claimed in claim 5, wherein said noise reduction means comprises at least one inductor connected in said first circuit path.

7. An electronic control apparatus as claimed in claim 1, wherein said MOS FET comprises a plurality of MOS FETs connected in respective current flow paths of a plurality of electrical loads, and wherein said drive circuit means selectively applies said stepped-up voltage to respective gate electrodes of said plurality of MOS FETs mutually independently.

8. An electronic control apparatus as claimed in claim 1, wherein said MOS FET is an N-channel MOS FET.

9. An electronic control apparatus as claimed in claim 1, wherein said main integrated circuit comprises second drive circuit means for selectively applying said stepped-up voltage to a gate electrode of a second MOS FET that is connected in a current flow path of a second electrical load, to effect on and off switching of said second MOS FET.

10. An electronic control apparatus as claimed in claim 1, comprising control circuit means for controlling said drive circuit means to selectively apply said stepped-up voltage to said gate electrode of said MOS FET, wherein:

said main integrated circuit comprises a power supply circuit coupled to receive said power source voltage from said power source voltage input terminal, for converting said power source voltage to an operating voltage, and an operating voltage output terminal coupled to receive said operating voltage; and

said operating voltage is supplied from said operating voltage output terminal to said control circuit means, for operating said control circuit means.

11. An electronic control apparatus as claimed in claim 10, wherein said power supply circuit comprises a switching type of power supply circuit.

12. An electronic control apparatus as claimed in claim 10, wherein said power supply circuit is adapted to produce a condition signal that is indicative of whether said operating voltage is being generated normally by said power supply circuit, and wherein said voltage step-up circuit of said main integrated circuit is coupled to receive said condition signal and is adapted to be set in an inoperative condition when said condition signal indicates that said operating voltage is not being generated normally.

13. An electronic control apparatus as claimed in claim 10, comprising noise reduction means connected to said power source input terminal of said main integrated circuit.

14. An electronic control apparatus as claimed in claim 13, wherein said noise reduction means comprises at least one element that is externally connected directly to said power source input terminal.

15. An electronic control apparatus as claimed in claim 14, wherein said noise reduction means comprises at least one of an inductor that is connected between a source of said power source voltage and said power source input terminal and a capacitor that is connected between said power source input terminal and a ground potential of said main integrated circuit.

16. An electronic control apparatus as claimed in claim 1, wherein said voltage step-up circuit comprises a charge pump circuit adapted to generate said stepped-up voltage by superimposing respective charges of a plurality of capacitors.

17. An electronic control apparatus as claimed in claim 1, wherein at least one circuit element that is a constituent element of said voltage step-up circuit and that has an effect upon an output drive capability of said voltage step-up circuit is connected to said main integrated circuit as an external component.

18. An electronic control apparatus as claimed in claim 17, wherein at least one circuit element that is a constituent element of said voltage step-up circuit and whose value determines an operating period of said voltage step-up circuit is connected to said main integrated circuit as an external component.

19. An electronic control apparatus as claimed in claim 17, wherein:

said voltage step-up circuit comprises an oscillator circuit that oscillates with an oscillation period that is determined by respective values of a resistor and a capacitor, and wherein said operating period of said voltage step-up circuit is determined by said oscillation period; and

at least one of said resistor and said capacitor is connected to said main integrated circuit as said external component.

20. An electronic control apparatus as claimed in claim 17, wherein said voltage step-up circuit comprises a charge pump circuit which performs switching of charges between a plurality of capacitors to generate said stepped-up voltage, and wherein said constituent element of said voltage step-up circuit that is connected to said main integrated circuit as an external component comprises at least one of said capacitors of said charge pump circuit.

21. An electronic control apparatus as claimed in claim 1, wherein a constituent element of said voltage step-up circuit that determines a target value of stepped-up voltage to be produced by said circuit is connected to said main integrated circuit as an external component.

22. An electronic control apparatus as claimed in claim 1, wherein:

said auxiliary integrated circuit comprises a second power source terminal coupled to receive said externally supplied power source voltage, a second voltage step-up circuit operating from said power source voltage supplied to said second power source terminal to produce a second stepped-up voltage that is higher than said power source voltage;

said second voltage step-up circuit is selectively set in an operative condition and an inoperative condition in accordance with whether or not a constituent element of said second voltage step-up circuit is connected to said auxiliary integrated circuit as an external component; and

when said second voltage step-up circuit is in said operative condition, said second stepped-up voltage is selectively applied to said gate electrode of said MOS FET to effect said on and off switching of said MOS FET.

23. An electronic control apparatus as claimed in claim 21, wherein said second voltage step-up circuit comprises a charge pump circuit which performs switching of charges between a plurality of capacitors to generate said stepped-up voltage, and wherein said constituent element of said second voltage step-up circuit that is connected to said auxiliary integrated circuit as an external component comprises at least one of said capacitors of said charge pump circuit.

24. An electronic control apparatus as claimed in claim 1, wherein:

said auxiliary integrated circuit comprises a second power source terminal coupled to receive said externally supplied power source voltage, a control signal input terminal, a second voltage step-up circuit operating from said power source voltage supplied to said second power source terminal to produce a second stepped-up voltage that is higher than said power source voltage;

said second voltage step-up circuit is selectively set in an operative condition and an inoperative condition in accordance with whether or not a predetermined signal is being externally applied to said control signal input terminal; and

when said second voltage step-up circuit is in said operative condition, said second stepped-up voltage is selectively applied by said drive circuit means to said gate electrode of said MOS FET to effect said on and off switching of said MOS FET.

25. An electronic control apparatus as claimed in claim 1, wherein said electronic control apparatus is adapted to be installed in a motor vehicle, and said electrical load comprises an apparatus of said motor vehicle.

26. An electronic control apparatus comprising:

a main integrated circuit, comprising

a power source terminal coupled to receive an externally supplied power source voltage,

a voltage step-up circuit operating from said power source voltage supplied to said power source terminal to produce a stepped-up voltage that is higher than said power source voltage,

a stepped-up voltage output terminal coupled to receive said stepped-up voltage, and

first drive circuit means for selectively applying said stepped-up voltage to a gate electrode of a first MOS FET (metal-oxide semiconductor field effect transistor) that is connected in a current flow path of a first electrical load, to effect on and off switching of said first MOS FET; and

at least one auxiliary integrated circuit, comprising

a stepped-up voltage input terminal coupled to receive said stepped-up voltage from said stepped-up voltage output terminal of said main integrated circuit, and

second drive circuit means for selectively applying said stepped-up voltage to a gate electrode of a second MOS FET that is connected in a current flow path of a second electrical load, to effect on and off switching of said second MOS FET.

27. An electronic control apparatus as claimed in claim 26, comprising noise reduction means coupled to said power source input terminal of said main integrated circuit.

28. An electronic control apparatus as claimed in claim 27, wherein said noise reduction means comprises at least one element that is externally connected directly to said power source input terminal.

29. An electronic control apparatus as claimed in claim 28, wherein said noise reduction means comprises at least one of an inductor that is connected between said source of said externally produced power source voltage and said power source input terminal and a capacitor that is connected between said power source input terminal and a ground potential of said main integrated circuit.

30. An electronic control apparatus as claimed in claim 26, wherein each said first and second MOS FET is an N-channel MOS FET.

31. An electronic control apparatus comprising control circuit means for generating a command signal to control driving of an electrical load, said electronic control apparatus comprising:

a main integrated circuit, said main integrated circuit comprising

a power source terminal coupled to receive an externally supplied power source voltage,

a voltage step-up circuit operating from said power source voltage supplied to said power source terminal to produce a stepped-up voltage that is higher than said power source voltage,

a stepped-up voltage output terminal coupled to receive said stepped-up voltage,

a power supply circuit coupled to receive said power source voltage from said power source voltage input terminal, for converting said power source voltage to an operating voltage, and

an operating voltage output terminal coupled to receive said operating voltage; and

at least one auxiliary integrated circuit, comprising

a stepped-up voltage input terminal coupled to receive said stepped-up voltage from said stepped-up voltage output terminal of said main integrated circuit, and

drive circuit means for selectively applying said stepped-up voltage to a gate electrode of a MOS FET (metal-oxide semiconductor field effect transistor) that is connected in a current flow path of said electrical load, to effect on and off switching of said MOS FET;

wherein said operating voltage is supplied from said operating voltage output terminal to said control circuit means, for operating said control circuit means, and said control circuit means generates a command signal for controlling said drive circuit means to selectively apply said stepped-up voltage to said gate electrode of said MOS FET.

32. An electronic control apparatus as claimed in claim 31, comprising noise reduction means coupled to said power source input terminal of said main integrated circuit.

33. An electronic control apparatus as claimed in claim 32, wherein said noise reduction means comprises at least one element that is externally connected directly to said power source input terminal.

34. An electronic control apparatus as claimed in claim 33, wherein said noise reduction means comprises at least one of an inductor that is connected between said source of said externally produced power source voltage and said power source input terminal and a capacitor that is connected between said power source input terminal and a ground potential of said main integrated circuit.

35. An electronic control apparatus as claimed in claim 31, wherein said MOS FET is an N-channel MOS FET.

36. An electronic control apparatus as claimed in claim 32, wherein said power supply circuit comprises a switching type of power supply circuit.

37. An electronic control apparatus as claimed in claim 31, wherein said power supply circuit is adapted to produce a condition signal that is indicative of whether said operating voltage is being generated normally by said power supply circuit, and wherein said voltage step-up circuit of said main integrated circuit is coupled to receive said condition signal and is adapted to be set in an inoperative condition when said condition signal indicates that said operating voltage is not being generated normally.