Charge Pump Negative Voltage Generation Circuit
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Solution Overview
Problem
Conventional negative supply voltage generating circuits for semiconductor integrated circuits have inefficient voltage conversion due to discharge paths formed from the output node to ground while charging the output capacitor, leading to low conversion efficiency.
Innovation Solution
A negative supply voltage generating circuit that includes a pulse generating circuit and a charge pump, where the pulse generating circuit generates first and second pulse signals with different pulse widths and a non-overlap period, allowing the charge pump to perform a charge pumping operation with a time interval between charging and transmitting charges, preventing simultaneous switching and thus avoiding discharge paths to ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If discharge paths are formed from output node to ground while charging output capacitor, then charging operation can be performed, but voltage conversion efficiency deteriorates
Solution Approach 1:
The charge pump circuit performs periodic charge pumping operations using non-overlapping first and second pulse signals with different pulse widths. The circuit alternates between charging the flying capacitor during the first pulse signal period and transmitting charges to the output capacitor during the second pulse signal period, ensuring that discharge paths are not active during charging phases, thereby improving voltage conversion efficiency through periodic isolated operation cycles
Solution Approach 2:
The flying capacitor is charged in advance during the first pulse signal period before the second pulse signal period begins. This preliminary charging action ensures that when the second pulse signal activates the charge transmission circuit, the flying capacitor is already prepared with sufficient charge, preventing simultaneous discharge paths and ensuring efficient charge transfer to the output capacitor without energy loss
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
This design enhances voltage conversion efficiency by preventing discharge paths to ground, resulting in a higher negative supply voltage generation, as demonstrated by simulation results showing improved voltage conversion efficiency compared to conventional circuits.
Implementation Method 1
The charge pump generates a negative supply voltage by performing a charge pumping operation in response to the first and second pulse signals
Implementation Method 2
The charge pump may charge the flying capacitor in response to the clock signal and the first pulse signal
Data Source
AI summary
A negative supply voltage generating circuit includes a pulse generating circuit and a charge pump. The pulse generating circuit generates a first pulse signal and a second pulse signal in response to a clock signal. The first and second pulse signals have pulse widths different from each other. The charge pump generates a negative supply voltage by performing a charge pumping operation in response to the first and second pulse signals, and has a time interval between a switch-on time duration for charging a flying capacitor and a switch-on time duration for transmitting charges to an output capacitor.