Switching power supply apparatus
AssigneeRohm Co., Ltd.
InventorKazuhiro HORII
Life of this patent
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Abstract
In a calibration step, a search processing unit changes a setting value so as to search for a critical value that corresponds to a boundary that defines whether or not overcurrent protection functions in a state in which a switching power supply apparatus is operated with a current at which overcurrent protection is to function in normal operation of the switching power supply apparatus. In a calibration step, a digital processor writes the setting value based on the critical value searched for by the search processing unit to nonvolatile memory. In the normal startup operation of the switching power supply apparatus, the digital processor reads the setting value from the nonvolatile memory and sets the setting value for the overcurrent detection circuit.
Claims16
A switching power supply apparatus comprising:
- at least one switching element;
- a control circuit structured to drive the at least one switching element,
- an overcurrent detection circuit structured to assert an overcurrent detection signal when a current that flows through a predetermined path of the switching power supply apparatus exceeds a threshold current, and to be capable of adjusting the threshold current according to a setting value,
- nonvolatile memory structured to hold a setting value to be supplied to the overcurrent detection circuit in normal operation of the switching power supply apparatus,
- a search processing unit structured to change the setting value in the calibration step so as to search for a critical value to be employed as the setting value that corresponds to a boundary that defines whether or not the overcurrent protection functions when the switching power supply apparatus operates with a current value at which the overcurrent protection is to function in normal operation thereof;
- and
- a digital processor structured to write the critical value obtained by the search by the search processing unit to the nonvolatile memory in the calibration step, and to read the critical value from the nonvolatile memory so as to supply the critical value as the setting value in the overcurrent detection circuit in a normal startup operation of the switching power supply apparatus.
A digital processor to be employed in a switching power supply apparatus, wherein the switching power supply apparatus comprises:
- at least one switching element,
- a control circuit structured to drive the at least one switching element;
- and
- an overcurrent detection circuit structured to assert an overcurrent detection signal when a current that flows through a predetermined path of the switching power supply apparatus exceeds a threshold current, and to be capable of adjusting the threshold current according to a setting value,
- and wherein the digital processor comprises:
- nonvolatile memory structured to hold the setting value;
- and
- a processing unit structured to receive an adjustment start signal, to enter a calibration mode with the adjustment start signal as a trigger, to change the setting value in a state in which the switching power supply apparatus is operated with a current at which overcurrent protection is to function in normal operation of the switching power supply apparatus, so as to search for a critical value that corresponds to a boundary that defines whether or not the overcurrent protection functions, to write the critical value obtained as a result of the search to be used as the setting value to the nonvolatile memory, and to read the critical value from the nonvolatile memory so as to set the critical value in the overcurrent detection circuit in a normal startup operation of the switching power supply apparatus.
A calibration method for a switching power supply apparatus, wherein the switching power supply apparatus comprises:
- at least one switching element;
- and
- an overcurrent detection circuit structured to assert an overcurrent detection signal when a current that flows through a predetermined path of the switching power supply apparatus exceeds a threshold current, and to be capable of adjusting the threshold current according to a setting value,
- and wherein the calibration method comprises:
- operating the switching power supply apparatus in a critical state in which overcurrent protection is to function in normal operation,
- searching for a critical value that corresponds to a boundary that defines whether or not the overcurrent protection functions while changing the setting value;
- and
- storing a value based on the critical value obtained by the search in the nonvolatile memory as the setting value to be set in the overcurrent detection circuit in normal operation of the switching power supply apparatus.
Dependencies are inferred from the claim text.