Power supply monitoring circuit, AC/DC conversion apparatus and control method of power supply monitoring circuit

• US 9,297,838 B2
• Filed: 07/18/2013
• Issued: 03/29/2016
• Est. Priority Date: 08/02/2012
• Status: Active Grant

• Current Assignee: Saturn Licensing LLC (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Watanabe, Hiroyuki, Yamane, Mitsuru
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US13/945,128
• Publication Number:
  US 20140036559A1
• Time in Patent Office: 985 Days
• Field of Search: 363/84, 363/89
• US Class Current: 1/1
• CPC Class Codes: G01R 19/00 Arrangements for measuring currents or voltages or for indicating presence or sign thereof G01R5/00 takes precedence; for measuring bioelectric currents or voltages A61B5/24
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 7/04 by static converters
• CPC Class Codes: 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

Abstract

There is provided a power supply monitoring circuit including a holding part holding, every time a local maximum value of a power supply voltage which fluctuates is detected, the local maximum value as a local maximum voltage value, a power stop detector detecting whether or not supply of the power supply voltage is stopped based on whether or not a state that a value of the power supply voltage is smaller than a first reference value according to the local maximum voltage value continues longer than a predetermined period, and a reference value controller decreasing the first reference value during a period in which the value of the power supply voltage exceeds a second reference value smaller than the first reference value and in which stop of the supply of the power supply voltage is detected.

Claims

1. A power supply monitoring circuit comprising:

a holding part holding, every time a local maximum value of a power supply voltage which fluctuates is detected, the local maximum value as a local maximum voltage value;

a power stop detector detecting whether or not supply of the power supply voltage is stopped based on whether or not a state that a value of the power supply voltage is smaller than a first reference value according to the local maximum voltage value continues longer than a predetermined period; and

a reference value controller decreasing the first reference value during a period in which the value of the power supply voltage exceeds a second reference value smaller than the first reference value and in which stop of the supply of the power supply voltage is detected.

2. The power supply monitoring circuit according to claim 1,

wherein the holding part includes a capacitor holding the local maximum voltage value, and

wherein the reference value controller decreases the first reference value by discharging the capacitor.

3. The power supply monitoring circuit according to claim 1,

wherein the first reference value is a value at which a ratio relative to the local maximum voltage value is a first ratio, and

wherein the second reference value is a value at which a ratio relative to the local maximum voltage value is a second ratio smaller than the first ratio.

4. The power supply monitoring circuit according to claim 1,

wherein the power stop detector includes

a power stop detection comparator comparing the value of the power supply voltage with the first reference value to output a result of the comparison as a first comparison result, and

a power stop detection circuit detecting whether or not the supply of the power supply voltage is stopped based on whether or not an output of the first comparison result indicating that the value of the power supply voltage is smaller than the first reference value continues longer than the predetermined period.

5. The power supply monitoring circuit according to claim 1,

wherein the reference value controller includes

a local maximum voltage value control comparator comparing the value of the power supply voltage with the second reference value to output a result of the comparison as a second comparison result, and

a reference value control circuit decreasing the first reference value during a period in which the second comparison result indicating that the value of the power supply voltage is larger than the second reference value is outputted and in which the stop of the supply of the power supply voltage is detected.

6. The power supply monitoring circuit according to claim 1,

wherein the holding part includes

a register holding the local maximum voltage value, and

wherein a local maximum voltage value controller decreases the first reference value by decreasing the local maximum voltage value read out from the register to update the register with the decreased local maximum voltage value.

7. The power supply monitoring circuit according to claim 1,

wherein the reference value controller decreases the first reference value during a period in which the local maximum voltage value is smaller than a predetermined threshold or a period in which the value of the power supply voltage is larger than the second reference value and in which the stop of the supply of the power supply voltage is detected.

8. An AC/DC conversion apparatus comprising:

a rectifier circuit generating a pulsating flow signal by rectifying an AC signal;

a holding part holding, every time a local maximum value of a power supply voltage as a voltage of the pulsating flow signal is detected, the local maximum value as a local maximum voltage value;

a power stop detector detecting whether or not supply of the power supply voltage is stopped based on whether or not a state that a value of the power supply voltage is smaller than a first reference value according to the local maximum voltage value continues longer than a predetermined period; and

a reference value controller decreasing the first reference value during a period in which the value of the power supply voltage exceeds a second reference value smaller than the first reference value and in which stop of the supply of the power supply voltage is detected.

9. A control method of a power supply monitoring circuit, comprising:

detecting, by a power stop detector, whether or not supply of a power supply voltage is stopped based on whether or not a state continues longer than a predetermined period, the state being that a value of the power supply voltage is smaller than a first reference value according to a local maximum voltage value which is held by a holding part holding, every time a local maximum value of the power supply voltage which fluctuates is detected, the local maximum value as the local maximum voltage value; and

decreasing, by a reference value controller, the first reference value during a period in which the value of the power supply voltage exceeds a second reference value smaller than the first reference value and in which stop of the supply of the power supply voltage is detected.