Power Supply Control Apparatus Voltage Drop Prevention
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Solution Overview
Problem
Conventional power supply control apparatuses experience sudden cutoffs of power supply due to a drop in input voltage, leading to improper switching of semiconductor switches and potential overcurrents, resulting in inefficient power management.
Innovation Solution
A power supply control apparatus with a semiconductor switch, a capacitor, a charging circuit, a diode, an input-voltage detection unit, and a driving unit that maintains the switch on by continuously charging the capacitor even when the input voltage falls below a threshold, preventing discharge and ensuring stable power supply through the current path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the charging circuit generates voltage based on input voltage, then the circuit complexity is reduced, but the reliability deteriorates when input voltage falls below threshold
Solution Approach 1:
The charging circuit is driven in advance when the switching signal indicates turn-on, charging the capacitor before the actual switching occurs. This preliminary charging ensures that even if input voltage subsequently drops below the threshold, the capacitor maintains sufficient voltage to keep the semiconductor switch turned on, preventing sudden power cutoff.
Solution Approach 2:
The charging circuit continues to operate continuously while the switching signal indicates turn-on, rather than operating intermittently based on voltage threshold detection. This continuous operation ensures the capacitor is always charged to the level needed to maintain the switch in the on-state, providing uninterrupted power supply to the load.
2Loss of energy
If the FET is switched off when input voltage drops, then the power consumption is reduced, but the productivity deteriorates due to sudden power cutoff
Solution Approach 1:
The capacitor is charged in advance to a sufficient voltage level before the input voltage drops, so that the switch remains in the on-state during the voltage drop. This preliminary charging action ensures continuous power supply to the load without sudden cutoff, maintaining productivity while allowing the system to tolerate temporary voltage drops.
3Ease of operation
If the charging circuit operates only when input voltage is above threshold, then the ease of operation is improved, but the stability deteriorates during voltage drops
Solution Approach 1:
The charging circuit operates continuously while the switching signal indicates turn-on, regardless of whether the input voltage is above or below the threshold. This continuous charging action maintains the capacitor voltage at a level sufficient to keep the switch in the on-state, ensuring stable power supply to the load during voltage drops without complicating the control logic.
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
Prevents sudden power cutoffs by maintaining the semiconductor switch in an on-state during voltage drops, preventing overcurrents and ensuring continuous power supply to the load, thereby enhancing power management efficiency.
Implementation Method 1
a capacitor whose one end is connected to the control terminal; a charging circuit configured to charge the capacitor
Implementation Method 2
a diode configured to prevent a current from flowing through the charging circuit from the capacitor
Data Source
AI summary
In a power supply control apparatus, if a switching signal input from a microcomputer to a control circuit instructs switching on of a semiconductor switch, when an input voltage that is input to the drain of the semiconductor switch is higher than or equal to a predetermined voltage, the control circuit drives a charging circuit. The charging circuit charges a capacitor (Cs) via a diode (D1). Accordingly, a voltage at the gate of the semiconductor switch taking a potential at the source of the semiconductor switch as a reference becomes higher than or equal to a predetermined voltage, and thus the semiconductor switch is switched on. While driving the charging circuit, the control circuit keeps driving the charging circuit even if the input voltage becomes lower than the predetermined voltage.