Circuit and method for detecting zero-crossings and brownout conditions on a single phase or multi-phase system

• US 9,581,626 B2
• Filed: 09/18/2013
• Issued: 02/28/2017
• Est. Priority Date: 11/14/2012
• Status: Active Grant

• Current Assignee: Diehl AKO Stiftung & Company KG
• Original Assignee: Diehl AKO Stiftung & Company KG
• Inventors: Schwind, Mathew
• Primary Examiner(s): Nguyen, Vinh
• Assistant Examiner(s): FORTICH, ALVARO E
• Application Number:
  US14/030,420
• Publication Number:
  US 20140132246A1
• Time in Patent Office: 1,259 Days
• Field of Search: 323/235, 327/78, 327/79, 327/530, 327/538, 327/540
• US Class Current: 1/1
• CPC Class Codes: G01R 19/16538 in AC or DC supplies G01R19/16519 and G01R19/16528 take precedence
• CPC Class Codes: G01R 19/175 Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero
• CPC Class Codes: G01R 25/00 Arrangements for measuring phase angle between a voltage and a current or between voltages or currents

Abstract

A circuit configuration detects zero-crossings and/or a brownout condition. The circuit configuration contains a zero-crossing detection circuit, a brownout detection circuit, an isolation and digitization circuit connected to the zero-crossing detection circuit and the brownout detection circuit, and a filtering circuit connected to the isolation and digitization circuit. The single circuit configuration can be used for detecting zero-crossings of single-phase and multi-phase systems as well as ascertaining a brownout condition of either the single-phase or the multi-phase systems.

Claims

1. A circuit configuration for detecting zero-crossings and a brownout condition of a power supply, the circuit configuration comprising:

a zero-crossing acquisition circuit for acquiring zero-crossings of single-phase signals and multiple-phase signals and having a zero-crossing signal terminal;

a brownout acquisition circuit having a brownout signal terminal connected to said zero-crossing signal terminal;

an isolation and digitization circuit having a terminal connected to both said zero-crossing signal terminal and said brownout signal terminal for detecting a zero-crossing and the brownout condition; and

a filtering circuit connected to said isolation and digitization circuit and outputting an output signal indicating at least the zero-crossings and the brownout condition.

2. The circuit configuration according to claim 1, wherein said isolation and digitization circuit has an optocoupler with an input side connected to said zero-crossing acquisition circuit and said brownout acquisition circuit and an output connected to said filtering circuit.

3. The circuit configuration according to claim 2, wherein said isolation and digitization circuit has a pull up resistor connected to said optocoupler.

4. The circuit configuration according to claim 1, wherein said zero-crossing acquisition circuit has a series circuit of resistors and a diode connected to said series circuit of resistors.

5. The circuit configuration according to claim 4, wherein:

said diode has a first terminal connected to said isolation and digitization circuit, said diode blocking negative half waves traversing said isolation and digitization circuit; and

said diode has a second terminal connected to said series circuit of resistors.

6. The circuit configuration according to claim 4, wherein said series circuit of resistors has two series circuits of resistors each containing two resistors connected in series.

7. The circuit configuration according to claim 1, wherein said brownout acquisition circuit including:

a first diode connected to said isolation and digitization circuit and blocking positive half waves traversing said isolation and digitization circuit;

a Zener diode circuit connected to said first diode, said Zener diode circuit having a given break down voltage; and

a resistor connected to said Zener diode and functioning as a current limiting resistor.

8. The circuit configuration according to claim 7, wherein:

said break down voltage is at least 130 voltages; and

said resistor is one of two resistors connected in series.

9. The circuit configuration according to claim 7, wherein said Zener diode circuit has at least two Zener diodes connected in series having a combined break down voltage of at least 130 volts.

10. The circuit configuration according to claim 1, wherein said Zener diode circuit has four Zener diodes connected in series having a combined break down voltage of at least 130 volts.

11. The circuit configuration according to claim 2, wherein said filtering circuit having an operational amplifier with a first input, a second input, and an output outputting the output signal.

12. The circuit configuration according to claim 11, wherein said filtering circuit having a feedback resistor connected between said output and said first input of said operational amplifier.

13. The circuit configuration according to claim 12, wherein said second input of said operational amplifier is connected to said output of said optocoupler.

14. A circuit configuration for detecting zero-crossings and a brownout condition of a power supply having a signal phase or multi-phases, the circuit configuration comprising:

a first terminal for connecting to a first phase of the power supply;

at least one second terminal for connecting to at least one second phase of the power supply;

a neutral terminal for connecting to the power supply;

a detection circuit having a first input coupled to said first terminal and said neutral terminal, a second input connected to said second terminal, and an output, said detection circuit acquiring zero-crossings of the first and second phases and a brownout condition of the first and second phases, said detection circuit further having an optocoupler with a first opto-terminal coupled to said second terminal, a second opto-terminal coupled to said first terminal and receiving both the zero crossings and the brownout condition, and a third opto-terminal.

15. The circuit configuration according to claim 14, said detection circuit further having:

a first diode having a first end connected to said first terminal and a second end connected to said second opto-terminal, said first diode blocking a negative voltage from said second opto-terminal;

a second diode having a first end coupled to said neutral terminal and a second end connected to said second opto-terminal, said second diode blocking a positive voltage from said second opto-terminal; and

an amplifier circuit having an input connected to said third opto-terminal and an output outputting a voltage dependent on the zero-crossings of the first and second phases and the brownout condition.

16. A method for operating a detector circuit for detecting zero-crossings and brownout conditions, which comprises the steps of:

acquiring a zero-crossing signal along a first signal path having a zero-crossing terminal;

acquiring a brownout condition signal along a second signal path having a brownout condition terminal, the brownout condition terminal being connected to the zero-crossing terminal;

submitting the brownout condition signal and the zero-crossing signal to a same terminal of control logic for determining a zero-crossing condition and the brownout condition.