Post Regulation Control Circuit for Reverse Current Protection
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Solution Overview
Problem
Conventional post regulation circuits in power supplies are vulnerable to short circuits, leading to excessive current and reverse currents that can damage both the post regulation and primary output circuits, causing system failure.
Innovation Solution
A post regulation control circuit with a monitor circuit comprising a pulse wave generation unit, power monitor unit, and logic unit that regulates the duty cycle of switch units to prevent reverse currents by detecting abnormal power levels and adjusting the driving pulse wave, thereby limiting switch operation and preventing damage to the primary output circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the post regulation circuit uses conventional current monitoring and integration control, then the switch ON period can be regulated, but when a short circuit occurs the induction current rises instantly to generate excessive over current that damages both the post regulation circuit and primary output circuit
Solution Approach 1:
The patent applies preliminary action by detecting abnormal conditions (voltage drop or current increase) at the very beginning of a short circuit event, before excessive current can build up. The monitor circuit detects the abnormality in real-time and immediately sends a shutdown signal to stop the switch unit operation, preventing the induction current from rising to dangerous levels that would cause reverse current and damage to primary output circuit components.
Solution Approach 2:
The patent implements feedback through the monitor circuit that continuously monitors the operating state of the post regulation circuit. The circuit detects abnormal conditions (voltage drop across switches or current increase) and provides real-time feedback by generating shutdown signals when thresholds are exceeded. This closed-loop feedback mechanism enables dynamic adjustment of switch duty cycle to prevent over current and reverse current generation.
2Reliability
If the PWM controller shrinks the rear edge of the driving pulse wave to limit current, then over current can be prevented, but when a short circuit occurs the induction current still rises rapidly within 2-3 clocks to generate excessive over current
Solution Approach 1:
The patent applies preliminary action by detecting abnormal conditions (voltage drop or current increase) at the very beginning of a short circuit event, before excessive current can build up. The monitor circuit detects the abnormality in real-time and immediately sends a shutdown signal to stop the switch unit operation, preventing the induction current from rising to dangerous levels that would cause reverse current and damage to primary output circuit components.
Solution Approach 2:
The patent applies skipping by immediately bypassing the normal gradual current limiting process and directly shutting down the switch unit when a short circuit is detected. Instead of relying on the PWM controller's gradual rear edge shrinking which takes too long, the monitor circuit triggers an immediate shutdown signal that rushes through the protection mechanism, stopping current flow within one clock cycle rather than allowing 2-3 clocks of excessive current flow.
3Device complexity
If the post regulation circuit operates without an independent protection mechanism, then the circuit structure can be simpler, but when a short circuit occurs the primary output circuit is damaged by reverse current generated from the post regulation circuit
Solution Approach 1:
The patent applies segmentation by dividing the protection function into a separate, independent monitor circuit that operates autonomously from the main PWM control circuit. The monitor circuit is segmented as a distinct functional block with its own detection and control logic, allowing it to provide independent protection without interfering with normal operation. This segmentation enables the protection mechanism to function independently even when the main control circuit is overwhelmed by short circuit conditions.
Solution Approach 2:
The patent introduces an intermediary protection mechanism in the form of the monitor circuit that acts as a mediator between the post regulation circuit and the primary output circuit. The monitor circuit detects abnormal conditions and intervenes by sending shutdown signals to prevent reverse current from reaching the primary output circuit. This intermediary layer provides protection without requiring fundamental changes to either the post regulation or primary output circuit designs.
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 provides an independent protection mechanism that prevents reverse currents from reaching the primary output circuit during short circuits, ensuring continuous operation and protecting the primary output circuit from damage.
Implementation Method 1
The transformer has a primary side 10 with a passing current controlled by a pulse width modulation (PWM) controller outputting a PWM signal and one set of switches. The transformer has a secondary side with multiple primary output circuits 11 and 12 to generate induction power through different windings.
Implementation Method 2
through inductors (L1 and L2) and capacitors to steady power waveforms to form two primary output power (IL1 and IL2) (12V and 5V)
Implementation Method 3
The switches 131 and 132 are controlled by a post control circuit (not shown in the drawings) which outputs one set of control signals (HS and LS). By integrating current flowing through the inductor 133 to get a voltage, a driving signal can be formed through amplification of an amplifier to control the ON period of the switches 131 and 132.
Data Source
AI summary
A post regulation control circuit aims to monitor ancillary output power generated from a power supply. The power supply includes at least one primary output circuit to provide a primary output power. A post regulation circuit obtains the primary output power and regulate to an ancillary output power. The monitor circuit sets an abnormal level and obtains a detection power from the post regulation circuit to compare with the abnormal level. Determining whether to output a driving pulse wave according to the detection power is over the abnormal level or not, or stop outputting the driving pulse wave.