Semiconductor Regulator Circuit Discharge Control
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Solution Overview
Problem
Series regulators with discharge circuits suffer from wasteful current consumption when turned off, as a constant current flows through the base of the discharge transistor, preventing the output voltage from dropping to 0 V.
Innovation Solution
A semiconductor integrated circuit with a control transistor, control circuit, discharge transistor, constant current source circuit, reference voltage generating circuit, voltage comparator circuit, and current amplification circuit, which controls the discharge transistor using an external control signal to manage current flow and rapidly lower the output voltage to ground level, minimizing wasteful current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a discharge circuit with a discharge transistor is used to rapidly lower the output voltage when the regulator is turned off, then the output voltage can drop quickly, but wasteful current consumption occurs because a constant current flows through the base of the discharge transistor even when the regulator is off
Solution Approach 1:
The patent applies dynamics by making the discharge transistor's base current dynamic rather than constant. The current flows only when needed (during shutdown) and stops when the regulator is operational, achieving both rapid voltage drop and low standby current consumption through time-dependent current control
Solution Approach 2:
The patent implements periodic action by controlling the discharge transistor to operate only during specific periods (shutdown transition) and remain inactive during normal operation. The control circuit enables the discharge transistor briefly to drop the output voltage, then disables it to stop current flow, creating a periodic on-off pattern that eliminates wasteful continuous current consumption
2Speed
If a discharge transistor is used to withdraw charge from the output capacitor, then the output voltage can be lowered rapidly, but the output voltage cannot fall to 0 V because the discharge transistor turns off at around 0.7 V
Solution Approach 1:
The patent uses an intermediary approach by introducing a control circuit that mediates between the discharge transistor and the output capacitor. This control circuit actively manages the discharge process, enabling the transistor to operate in its linear region rather than being limited by its cutoff voltage, thereby achieving precise control over the output voltage descent to near 0 V
3Area of stationary object
If multiple circuits (constant current source, reference voltage generator, voltage comparator, current amplification) are integrated into a single semiconductor integrated circuit, then the chip area is kept compact, but the circuit complexity increases
Solution Approach 1:
The patent applies merging by combining multiple functional circuits (constant current source, reference voltage generator, voltage comparator, and current amplification circuit) into a single integrated discharge control circuit. This consolidation reduces the overall chip area while managing complexity through functional integration and shared circuit elements
Solution Approach 2:
The patent implements universality by designing the integrated circuit to perform multiple functions: generating constant current, creating reference voltage, comparing voltages, amplifying current, and controlling the discharge transistor. This multi-functional design eliminates the need for separate discrete circuits, reducing chip area while consolidating control logic into a unified structure
Data Source
AI summary
A semiconductor integrated circuit for a regulator, including: a control transistor; a control circuit; and a discharge circuit, wherein the discharge circuit includes: a constant current source circuit; a reference voltage generating circuit; a voltage comparator circuit; and a current amplification circuit, and wherein the control circuit is configured to control the control transistor in response to the control signal, and the discharge circuit is configured to operate the discharge transistor by the amplified current amplified by the current amplification circuit.