Driving Circuit Zero Current Shutdown Bias Elimination
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Solution Overview
Problem
Integrated chips experience power loss due to bias current during off conditions, reducing the effective lifetime of power supplies like batteries, and this loss increases with higher input voltage sources.
Innovation Solution
A driving circuit with zero current shutdown, featuring a linear regulating circuit, a start-up circuit with a threshold voltage, and a power switch that generates an internal enable signal only when the external enable signal exceeds the threshold, eliminating bias current during shutdown and maintaining efficient linear regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the chip is turned off to save power, then power consumption is reduced, but bias current still flows causing avoidable power loss
Solution Approach 1:
The circuit dynamically adjusts the shutdown current based on the external enable signal voltage level. When the enable signal is below the threshold voltage, the circuit enters shutdown mode with minimal current consumption. When the enable signal exceeds the threshold, the circuit transitions to normal operation mode with adequate bias current, allowing the system to adapt its power consumption to operational requirements.
Solution Approach 2:
The invention changes the voltage parameter of the external enable signal to control the operational state of the circuit. By comparing the enable signal voltage against a threshold voltage, the circuit switches between two distinct current consumption states: a low current shutdown state and a normal bias current state, thereby optimizing power loss based on the enable signal parameter.
2Power
If the input voltage source is increased to provide more power, then available power increases, but power loss increases proportionally
Solution Approach 1:
The circuit uses the external enable signal as a feedback mechanism to regulate bias current consumption. The enable signal voltage level provides information about the desired operational state, and the circuit responds by adjusting its current consumption accordingly, creating a feedback loop that prevents excessive power loss even when high input voltage is available.
Solution Approach 2:
The bias current is made dynamic rather than fixed, allowing it to adjust based on the enable signal voltage. This dynamic current adjustment ensures that the circuit only consumes necessary bias current when actually enabled, preventing proportional power loss that would occur with fixed bias current designs regardless of input voltage level.
3Speed
If bias current is maintained during shutdown to keep circuits ready, then startup time is reduced, but power loss increases
Solution Approach 1:
The circuit performs preliminary action by maintaining the capability to quickly transition from shutdown to operation through the voltage-threshold mechanism. When the enable signal rises above the threshold voltage, the circuit is already prepared to immediately establish appropriate bias current levels, achieving fast startup without requiring continuous bias current during shutdown, thus balancing startup speed with power savings.
Data Source
AI summary
Methods and circuits related to a driving circuit with zero current shutdown are disclosed. In one embodiment, a driving circuit with zero current shutdown can include: a linear regulating circuit that receives an input voltage source, and outputs an output voltage; a start-up circuit having a threshold voltage, the start-up circuit receiving an external enable signal; a first power switch receiving both the output voltage of the linear regulating circuit and the external enable signal, and that generates an internal enable signal, the internal enable signal being configured to drive a logic circuit; when the external enable signal is lower than a threshold voltage, the driving circuit is not effective; when the external enable signal is higher than the threshold voltage, the start-up circuit outputs a first current; and where the output voltage at the first output terminal is generated by the linear regulating circuit based on the first current.