Linear Voltage Regulator Circuit for Low-Spike Voltage Switching
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Solution Overview
Problem
In dual mode systems, the switching between different power modes causes spike currents that affect the reliability of power supply generators, particularly in secure digital card hosts and RGMII systems where mid-bias supply is used to ensure circuit safety.
Innovation Solution
A power supply generator system with a voltage regulator circuit and power switch circuit that includes a control circuit to manage transitions between different operational voltages, using a selection circuit to control the activation and deactivation of the voltage regulator and power switch circuits, and a detection circuit to gradually turn on the power switch circuit, reducing spike currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the power switch circuit is turned on rapidly during voltage mode transitions, then the switching speed is improved, but spike currents occur that reduce the reliability of the power supply generator
Solution Approach 1:
The voltage regulator circuit is activated in advance before the power switch circuit to pre-charge the output node to a first voltage level (e.g., half of the supply voltage). This preliminary action ensures that when the power switch circuit turns on, the voltage difference is reduced, thereby minimizing spike currents while maintaining fast switching speed.
Solution Approach 2:
The system dynamically switches between two power supply modes: in the first mode, only the voltage regulator circuit is active to provide a controlled voltage ramp-up; in the second mode, both the voltage regulator circuit and power switch circuit are active to provide full power. This dynamic configuration optimizes both reliability during transitions and speed during steady-state operation.
2Reliability
If the voltage regulator circuit is used to pull up the output voltage to a first voltage level before switching, then spike currents are reduced, but the transition time between voltage modes increases
Solution Approach 1:
The voltage regulator circuit operates continuously in the background to maintain the output node at a controlled voltage level, while the power switch circuit provides additional current when needed. This continuous operation eliminates the need for sequential switching, reducing transition time while maintaining the benefits of controlled voltage ramp-up for spike current reduction.
3Reliability
If the mid-bias supply is utilized to ensure circuit safety during mode switching, then the safety of the circuit is improved, but spike currents still occur that impact the reliability of power supply generators
Solution Approach 1:
The voltage regulator circuit acts as an intermediary between the power supply generator and the output node during mode transitions. It provides a controlled, gradual voltage increase that mediates the abrupt changes caused by direct power switch circuit activation, thereby reducing spike currents while maintaining circuit safety through the mid-bias supply.
Data Source
AI summary
A device includes a voltage regulator circuit configured to pull up a voltage at an output terminal to equal to half of a supply voltage; multiple first transistors coupled between the output terminal and a voltage terminal providing the supply voltage; and a control circuit configured to pull down gate voltages of the first transistors from the supply voltage to a voltage level between the supply voltage and a ground voltage at a first time. The first transistors are configured to pull up the voltage at the output terminal to the supply voltage at a second time.