Charge Pump Circuit With Dynamic Back Bias Control
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Solution Overview
Problem
Charge pump circuits face issues with large leakage currents in transistor devices due to process and temperature variations, and the use of resistive devices for voltage regulation leads to high power consumption, which is undesirable for low-power applications.
Innovation Solution
A charge pump circuit that includes a transistor array with back gate terminals coupled to the charge pump output voltage and a control circuit to regulate the back bias voltage of the transistors, allowing the charge pump output voltage to be dynamically adjusted to reduce leakage current and eliminate the need for resistive devices for voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed charge pump output voltage is used to drive transistor devices, then the circuit operation is simple, but large leakage current occurs due to process and temperature variations
Solution Approach 1:
The charge pump output voltage is made dynamic rather than fixed. The control circuit continuously adjusts the charge pump output voltage based on feedback from the back bias voltage sensing circuit, allowing the voltage to adapt to process and temperature variations, thereby reducing leakage current while maintaining simple circuit operation
Solution Approach 2:
A feedback mechanism is implemented where the back bias voltage of the transistor devices is sensed and fed back to the control circuit. The control circuit uses this feedback information to regulate the charge pump output voltage, creating a closed-loop system that automatically compensates for variations and minimizes leakage current
2Reliability
If a resistive device is used to sense or regulate the output voltage of the charge pump, then voltage regulation is achieved, but large current consumption and high power consumption occur
Solution Approach 1:
The patent replaces the traditional resistive voltage sensing mechanism with a capacitive-based back bias voltage sensing circuit. This substitution eliminates the need for continuous current flow through resistive elements, achieving voltage regulation through capacitive coupling and digital control, thereby dramatically reducing power consumption while maintaining reliable voltage regulation
Solution Approach 2:
The sensing mechanism changes from resistive (continuous current-based) to capacitive (charge-based). By changing the fundamental physical parameter used for sensing from resistance to capacitance, the system achieves voltage regulation without the continuous power consumption inherent in resistive devices
3Device complexity
If traditional charge pump control is used, then the circuit is simple, but large substrate area is required
Solution Approach 1:
The control circuit integrates multiple functions into a single unified structure. The back bias voltage sensing circuit, charge pump control logic, and voltage regulation functions are merged into one compact control unit, reducing the overall substrate area while maintaining circuit simplicity and avoiding the need for separate resistive sensing circuits
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces leakage current in transistor arrays, enables low-power operation, and simplifies charge pump control, making it suitable for compact IC applications like memory and microcontroller circuits with reduced substrate area.
Implementation Method 1
A charge pump uses capacitive devices as energy storage elements to convert an input direct current (DC) voltage into a desired output DC voltage
Implementation Method 2
A back gate terminal of the first transistor device is coupled to the charge pump output voltage
Data Source
AI summary
Embodiments of a charge pump circuit and a method for operating a charge pump circuit are disclosed. In an embodiment, a charge pump circuit includes a charge pump configured to generate a charge pump output voltage, a transistor array including multiple transistor devices that includes at least one transistor device having a back gate terminal coupled to the charge pump output voltage, and a control circuit configured to control the charge pump output voltage so as to regulate the back bias voltage of the transistor devices within the transistor array. Other embodiments are also described.