Four-Phase Charge Pump Circuit with Auxiliary Start-Up Transistors
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Solution Overview
Problem
Conventional charge pump circuits often fail to start up properly, resulting in an inability to provide a normal voltage level, which affects the functionality of electronic devices that rely on them.
Innovation Solution
A four-phase charge pump circuit is designed with multiple boosting stages driven by a four-phase clock signal, incorporating two branch charge pumps and auxiliary start-up transistors in each stage to ensure proper initialization and operation of the main pass transistors, preventing start-up failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional charge pump circuit design is used, then the circuit structure is simple, but the circuit cannot start up properly and cannot provide normal voltage level
Solution Approach 1:
The auxiliary start-up transistors are activated before the main pass transistors to pre-charge the control nodes and establish proper voltage levels. This preliminary action ensures that when the main pass transistors are turned on, the control gates are already at the correct potential, preventing start-up failures and ensuring reliable operation of the charge pump circuit.
2Reliability
If auxiliary start-up transistors are added to each boosting stage, then the start-up reliability is improved, but the device complexity increases
Solution Approach 1:
The charge pump circuit is divided into multiple boosting stages, and each stage is further segmented into main pass transistors and auxiliary start-up transistors. This segmentation allows the auxiliary transistors to be independently controlled and activated only when needed for start-up, improving reliability while managing complexity through modular design.
Solution Approach 2:
The auxiliary start-up transistors perform preliminary charging of the control nodes before the main pass transistors are activated. This preliminary action ensures proper initialization of each boosting stage, preventing start-up failures without requiring continuous operation of additional transistors, thus managing complexity while improving reliability.
Data Source
AI summary
A four-phase charge pump circuit provided includes multiple boosting stages. Each boosting stage includes two branch charge pumps. Each branch charge pump includes a main pass transistor and a pre-charge transistor. Two ends of the main pass transistor serve as a first node and a second node of the branch charge pump respectively. A first end, a second end and a control end of the pre-charge transistor are coupled to a control end of the main pass transistor, a second node and a first node of the branch charge pump respectively. At least one boosting stage further includes two auxiliary start-up transistors. Two ends of each auxiliary start-up transistor are coupled to the control end of one main pass transistor and the second node of the branch charge pump respectively. A control end of each auxiliary start-up transistor is coupled to the control end of one main pass transistor.