Switching Power Supply Device With Dynamic Bleeder Circuit
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Solution Overview
Problem
Conventional switching power supply devices with low-side diode rectification configurations face power loss and heat generation due to the use of bleeder resistors, especially under heavy load conditions, as they cannot perform discontinuous operation effectively.
Innovation Solution
A switching power supply device is designed with a current detection circuit, voltage detection circuit, and control circuit that manages a bleeder circuit to supply load current only when necessary, using a diode at the low-potential side and employing current mode control to minimize power loss by activating the bleeder circuit only when the load current is low, thereby reducing power loss and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bleeder resistor is used to supply load current in a low-side diode rectification configuration, then the device can maintain operation under light load conditions, but power loss and heat generation increase under heavy load conditions
Solution Approach 1:
The patent applies dynamics by making the bleeder circuit configurable and controllable through the control circuit. The bleeder resistance can be dynamically adjusted or switched based on load conditions, allowing the system to optimize between maintaining operation stability under light load while reducing power loss under heavy load conditions. This is achieved by integrating the bleeder circuit into the controllable switching architecture rather than using a fixed resistor.
Solution Approach 2:
The patent changes the parameter of bleeder resistance from a fixed value to a variable parameter that can be adjusted based on operating conditions. By controlling the bleeder circuit through switching elements and control logic, the resistance value can be changed dynamically to match load requirements, thereby reducing power loss (P=I²R) when full bleeder current is not needed while maintaining reliability when required.
2Stability of the object's composition
If the switching power supply operates in continuous mode, then stability is maintained, but power loss increases due to continuous current flow through the diode
Solution Approach 1:
The patent implements periodic action by enabling the switching power supply to operate in discontinuous conduction mode (DCM) rather than continuous conduction mode (CCM). The switching element and diode conduct current in periodic pulses rather than continuously, allowing the inductor current to reach zero between switching cycles. This periodic operation reduces average power loss in the diode while maintaining output voltage stability through proper control of the switching duty cycle and frequency.
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
The solution effectively reduces power loss and stabilizes output voltage by selectively activating the bleeder circuit during low load current conditions, preventing over-voltage and minimizing power consumption, thus enhancing efficiency and stability.
Implementation Method 1
outputting a fly-wheeling current generated by the coil when the switching element is turned off
Implementation Method 2
a low-side circuit configuration by diode rectification
Data Source
AI summary
A switching power supply device includes a switching element and a diode and generates an output voltage by supplying current to a coil by controlling the switching element to turn on and off. A current detection circuit detects a current flowing in the switching element. A voltage detection circuit monitors a voltage at an output terminal OUT. A control circuit controls the switching element to turn on and off by a current control mode based on a current detection signal and a feedback voltage. The control circuit drives a bleeder circuit to supply a load current to the output terminal when a level of the current detection signal is lower than a predetermined level.