Switching Power Supply Voltage Detection for Standby Power Reduction
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Solution Overview
Problem
Conventional switching power supplies face challenges in reducing standby power consumption due to bulky and expensive high-withstand voltage components, and issues with feedback control leading to increased power consumption when load current decreases.
Innovation Solution
A switching power supply design that includes a transformer with a primary and secondary winding, a switching element, a rectifying/smoothing circuit, a voltage detecting circuit, and a feedback amplifier, where the voltage detecting circuit supplies a higher voltage to the feedback amplifier upon receiving a standby mode command, allowing the control circuit to adjust the switching element and reduce output voltage during low load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-withstand voltage components are used on the primary side to ensure safety, then reliability is improved, but device complexity and size increase
Solution Approach 1:
The patent extracts the voltage detection function from the primary side to the secondary side. By placing the voltage detecting circuit on the secondary side of the transformer, the system eliminates the need for high-withstand voltage components on the primary side, thereby reducing component complexity and size while maintaining safety through feedback control.
Solution Approach 2:
The patent introduces a feedback mechanism as an intermediary between the secondary side voltage detection and the primary side switching control. The feedback amplifier and control circuit act as mediators that transmit voltage information across the transformer isolation barrier, enabling safe voltage monitoring without direct primary side component exposure to high voltages.
2Stability of the object's composition
If feedback control is maintained during standby mode, then output voltage stability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic control of the switching element during standby mode by adjusting the duty ratio based on detected voltage levels. The control circuit dynamically modifies switching parameters to maintain output voltage stability while minimizing power consumption, transitioning from fixed-duty-cycle operation to adaptive duty-ratio control.
Solution Approach 2:
The patent changes the switching parameter (duty ratio) based on the detected output voltage level during standby mode. When voltage drops below a threshold, the duty ratio is increased to restore voltage; when voltage is sufficient, the duty ratio is reduced to minimize power consumption. This parameter adaptation resolves the contradiction between stability and energy efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables a low-cost, compact switching power supply that efficiently reduces standby power consumption by maintaining stable output voltage and preventing overdrive states, thereby minimizing power consumption during low load conditions.
Implementation Method 1
a transformer (10) including a primary winding (10a) and a secondary winding (10b), so that an AC voltage based on a current supplied to the primary winding (10a) is output through the secondary winding (10b)
Implementation Method 2
a switching element (61) which controls current supply to the primary winding (10a)
Implementation Method 3
a rectifying/smoothing circuit (12, 13) which converts the AC voltage output from the secondary winding (10b) to a DC voltage
Implementation Method 4
a feedback amplifier (4) which is supplied with the DC voltage detected by the voltage detecting circuit (1, 2) as one input and which is supplied with a reference voltage as the other input, so as to output the difference between the values of these input voltages
Data Source
AI summary
A switching power supply includes: transformer 60 which includes a primary winding and a secondary winding and outputs, through the secondary winding, an AC voltage based on the current supplied to the primary winding; switching element 61 which controls current supply to the primary winding; rectifying/smoothing circuit 65 which converts the AC voltage output from the secondary winding into a DC voltage; voltage detecting circuit 62 which detects the DC voltage converted by rectifying/smoothing circuit 65; feedback amplifier 63 which is supplied with the DC voltage detected by voltage detecting circuit 62 as one input and which is supplied with a reference voltage as the other input, so as to output a difference between the input voltage values; and control circuit 64 which controls switching element 61, so as to eliminate the difference detected at feedback amplifier 63. Upon receipt of an instruction signal from the outside, voltage detecting circuit 62 supplies to feedback amplifier 63, a voltage higher than the voltage output before receipt of the instruction signal.