Charge Pump Bulk Voltage Controller for Latch-Up Prevention
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Solution Overview
Problem
Charge pumps in electronic devices face challenges in maintaining a constant boosted voltage output due to current consumption, leading to inefficiencies and potential latch-up phenomena, especially in CMOS charge pumps using PMOS transistors where bulk node changes affect output voltage reliability.
Innovation Solution
A power supply device with a boost circuit unit and bulk voltage controller that uses PMOS transistors to control the connection between the output node and bulk node based on output voltage levels, ensuring stable voltage delivery without threshold voltage drops and preventing latch-up by interlocking gate and output voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a cross-coupled charge pump uses PMOS transistors with bulk node directly connected to output node, then boosted voltage is delivered without threshold voltage drop, but latch-up phenomenon occurs and power loss increases
Solution Approach 1:
The patent divides the bulk node connection into two separate controllable paths: one path connects the first bulk node to the first output node, and another path connects the second bulk node to the second output node. Each connection is independently controlled by control signals, allowing selective connection and disconnection to prevent latch-up while maintaining efficient voltage transfer when needed.
Solution Approach 2:
The patent implements dynamic control of the bulk node connections by using control circuits that adjust the connection state based on operating conditions. The control signals dynamically enable or disable the bulk-to-output connections, transitioning from a static direct connection to a dynamically controlled connection that adapts to prevent latch-up during startup or abnormal conditions while maintaining efficiency during normal operation.
2Power
If current consumption increases at output terminal, then more power is delivered to load, but boosted voltage cannot be constantly maintained
Solution Approach 1:
The patent incorporates control circuits that monitor the output voltage and current consumption conditions, and use this information to adjust the operation of the charge pump. The control signals regulating the bulk node connections and transistor operations are based on feedback from the output conditions, enabling the system to maintain stable boosted voltage even when current consumption varies due to load changes.
3Loss of energy
If leakage current flows through bulk node, then power loss occurs, but latch-up phenomenon may also occur
Solution Approach 1:
The patent applies preliminary anti-action by implementing control mechanisms that prevent latch-up before it can occur. The control circuits detect conditions that may lead to latch-up (such as during startup or when leakage current increases) and proactively adjust the bulk node connections or transistor operations to counteract the developing latch-up condition, rather than waiting for the latch-up to fully manifest.
Data Source
AI summary
A power supply device includes; first/second boost circuits that boost voltages applied to a first/second boost nodes in response to a first/second main signals, and respectively operated first/second transmission unit that control provision of boosted voltages to an output node. The power supply device also includes a bulk voltage controller connected between the boosted nodes and controlling a connection between the output node and a bulk node in response to a bulk control signal. Voltages respectively applied to the first and second transmission units are determined in response to an output node voltage, as well as the first/second main signals.