Method and circuit for monitoring power supply
AssigneeInfsitronix Technology Corporation
InventorsYuan-Kai Cheng, Chun-Chiang Chen
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Abstract
The present application provides method and circuit for monitoring a power supply, which firstly obtains an auxiliary side voltage from a switching power supply and then adopts a divided voltage circuit to obtain a divided voltage from the auxiliary side voltage, for detecting the divided voltage and a detected current flowed in the detection circuit with adopting a first detection circuit and a second detection circuit in an switch circuit to correspondingly generate a first and a second detection signals, which is corresponding to an ambient temperature and an output voltage of the power supply. Hereby, the power supply is monitored.
Claims19
A method for monitoring power supply, comprising:
- sensing a winding voltage of a switching power supply using an auxiliary winding for acquiring an auxiliary side voltage;
- acquiring a divided voltage of said auxiliary side voltage using a voltage division circuit, said voltage division circuit including a first impedance element and a second impedance element, and said second impedance element including a thermistor,
- using a first detection circuit to detect said divided voltage and generate a first detection signal in a switching period of said switching power supply;
- and
- using a second detection circuit coupled between said first impedance element and said second impedance element to form a detection current flowing to said second detection circuit and generating a second detection signal in said switching period;
- wherein said first detection circuit and said second detection circuit operate respectively when the secondary winding of said switching power supply is discharging in said switching period and said first detection signal and said second detection signal correspond to an ambient temperature and an output voltage of said switching power supply respectively.
A circuit for monitoring power supply, applied for a switching power supply, said switching power supply including an auxiliary winding for sensing a winding voltage and acquiring an auxiliary side voltage, and comprising:
- a voltage division circuit, coupled to said auxiliary winding, including a first impedance element and a second impedance element, and said second impedance element including a thermistor;
- a first detection circuit, coupled between said first impedance element and said second impedance element;
- and
- a second detection circuit, including a switch coupled between said first impedance element and said second impedance element;
- wherein a switching period of said switching power supply and when the secondary winding of said switching power supply is discharging, said switch of said second detection circuit is opened or closed, respectively;
- when said switch is opened, said first detection circuit detects a divided voltage of said auxiliary side voltage and generates a first detection signal in said switching period of said switching power supply;
- when said switch is closed, said second detection circuit is coupled to said voltage division circuit to form a detection current flowing to said second detection circuit and said second detection circuit detects said detection current for generating a second detection signal in said switching period of said switching power supply;
- and said first detection signal and said second detection signal correspond to an ambient temperature and an output voltage of said switching power supply respectively.
Dependencies are inferred from the claim text.