Power Supply Circuit Discharging Capacitor Rush Current
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Solution Overview
Problem
Power supply circuits with regulators capable of switching ON/OFF experience a rush current when transitioning from OFF to ON, damaging connected electronic components and reducing battery voltage, due to accumulated electrical charges in capacitors.
Innovation Solution
Incorporating a discharging circuit that gradually discharges electrical charges from the capacitor while the regulator is in the OFF state, allowing the reference voltage to increase gradually when switching to ON, preventing rush currents and maintaining stable output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the regulator is switched from OFF to ON while the standard voltage is outputted from the standard voltage generator, then the regulator can provide power output, but a rush current is outputted from the regulator which damages electronic components and reduces battery voltage
Solution Approach 1:
The patent applies preliminary action by gradually charging the capacitor connected in parallel to the regulator before the regulator is switched ON. This is achieved by controlling the standard voltage generator to output standard voltage before the regulator activation, which charges the capacitor through a current-limiting resistor. When the regulator is subsequently switched ON, the pre-charged capacitor prevents rush current by providing immediate voltage support, thus resolving the contradiction between power output capability and rush current prevention
Solution Approach 2:
The patent uses a capacitor connected in parallel to the regulator as an intermediary element. This capacitor acts as a mediator between the standard voltage generator and the regulator output, smoothing voltage transitions and preventing rush current. The capacitor charges gradually through a current-limiting resistor and then discharges to support the regulator output, effectively mediating the harmful rush current while maintaining power output capability
2Object-affected harmful factors
If an overcurrent limiter is included in the regulator to prevent rush current, then rush current is prevented, but the configuration of the regulator becomes complicated
Solution Approach 1:
The patent extracts the rush current prevention function from the regulator itself and implements it externally using a capacitor connected in parallel to the regulator and a current-limiting resistor. By removing the overcurrent limiter from the regulator configuration and replacing it with an external capacitor-based solution, the patent achieves rush current prevention while simplifying the regulator's internal configuration, thus resolving the contradiction between rush current prevention and device complexity
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 prevents rush currents and protects electronic components from voltage drops, ensuring stable operation and prolonging battery life by gradually charging capacitors before switching the regulator ON.
Implementation Method 1
a capacitor (4) connected in parallel to the regulator (3) between the standard voltage generator (2) and the regulator (3)
Data Source
AI summary
A power supply circuit includes a standard voltage generator; a regulator to control an output voltage, and to be capable of being switched ON/OFF; a capacitor in parallel between the standard voltage generator and the regulator; a discharging circuit including a first switch and a second switch configured to discharge electrical charges from the capacitor via the second switch while the regulator is in an OFF state; and a starting controller configured to transmit a signal for controlling the first switch and the second switch. The first switch is connected in series between the standard voltage generator and the regulator. The second switch has one end connected to a connection node between the first switch and the regulator, and has another end connected to a ground. When the first switch is in OFF state, the second switch is turned to ON state while the regulator is in OFF state.