Step-Down Power Supply Bias Current Control for Voltage Transition
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Solution Overview
Problem
In data processing devices, the self power consumption of step-down power supply circuits hinders power consumption reduction, and there are delays in transitioning between low power consumption and normal operation states due to voltage level changes.
Innovation Solution
A data processing device with a step-down power supply circuit that includes a bias current control circuit to manage the bias current flowing through an auxiliary path, allowing for quick changes in the internal operating voltage during state transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the width of the gate electrode of the driver MOS transistor is increased to ensure adequate driving ability at low externally supplied voltage, then the driving ability is improved, but the capacity of the gate electrode is increased causing delayed voltage level transition
Solution Approach 1:
The patent introduces a boot capacitor connected to the gate electrode of the driver MOS transistor to preliminarily store charge before the transistor needs to operate. This preliminary charging action ensures that when the transistor switches, it can quickly establish the required voltage level without delay, resolving the contradiction between having sufficient driving ability and achieving fast voltage transition.
2Power
If the gate insulating film is thickened to apply higher voltage than internal operating voltage to the gate electrode, then the driving ability is improved, but the capacity of the gate electrode is increased causing delayed transition
Solution Approach 1:
The boot capacitor is charged in advance through a charging path that includes a charging transistor and resistance element. This preliminary charging action stores the necessary energy in the capacitor before it is needed, allowing the driver MOS transistor to quickly switch and establish the required voltage level at the output node without delay when transitioning between operational states.
3Adaptability or versatility
If a step-down power supply circuit is incorporated to generate internal operating voltage, then the operating voltage range is extended, but the self power consumption of the circuit hinders power consumption reduction
Solution Approach 1:
The patent implements intermittent operation where the data processing device alternates between active and low-power states. During low-power states, the clock supply to internal functional blocks is stopped or frequency is reduced, and the power supply voltage is decreased. The boot capacitor maintains the gate voltage during these transitions, enabling the device to achieve significant power consumption reduction while maintaining adaptability to different operating voltage requirements.
Data Source
AI summary
A data processing device includes a load circuit including a central processing unit and operated by supplied electric power, a step-down power supply circuit stepping down an external power supply voltage and including an output node coupled to the load circuit, the step-down power supply circuit including a first step-down unit stepping down the external power supply voltage, and a bias current control circuit controlling a magnitude of bias current flowing through an auxiliary path from the output node to a ground, the auxiliary path is separate from a path to the load circuit, and a control circuit increasing the magnitude of the bias current, prior to a change of an operation state of the load circuit by which a relatively large change occurs to an amount of current consumed by the load circuit.