Charge Pump Clock Frequency and Amplitude Control
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Solution Overview
Problem
Charge pumps face challenges in generating high voltage with high loading current due to output voltage decrease as load current increases, limiting their dynamic working range.
Innovation Solution
The solution involves dynamically sensing load current to regulate both clock frequency and amplitude, using current mirrors and oscillation units to adjust the clock signal frequency and amplitude proportionally with load current, and incorporating an over-voltage detection unit to prevent excessive voltage generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If load current increases, then power delivery capability is improved, but output voltage decreases
Solution Approach 1:
The patent implements a feedback mechanism where the oscillating signal frequency is dynamically adjusted based on the load current. A current sense signal proportional to the load current is generated, and this signal controls the oscillation frequency of the charge pump. When load current increases, the oscillation frequency increases accordingly, maintaining output voltage stability while accommodating higher power delivery requirements.
Solution Approach 2:
The patent makes the charge pump dynamic by allowing the oscillation frequency to vary with load conditions. Instead of a fixed frequency operation, the system continuously adapts the switching frequency based on the actual load current, enabling the charge pump to optimize its performance across different operating conditions and maintain voltage stability under varying power demands.
2Power
If oscillation frequency is increased to maintain voltage under high load, then power delivery is improved, but energy loss increases
Solution Approach 1:
The feedback mechanism ensures that the oscillation frequency is increased only when necessary, i.e., when load current increases. The current sense signal provides real-time information about load conditions, and the control system adjusts the frequency proportionally. This prevents unnecessary frequency increases and associated energy losses when the load is light, while still enabling high power delivery when needed.
Solution Approach 2:
The patent changes the operating parameter (oscillation frequency) dynamically based on load conditions. By adjusting the frequency proportional to the load current through the current mirror circuit, the system optimizes the balance between power delivery capability and energy efficiency, avoiding fixed high-frequency operation that would waste energy during low-load conditions.
3Reliability
If current sensing and frequency regulation circuitry is added, then output voltage stability is improved, but device complexity increases
Solution Approach 1:
The oscillating signal generation circuit serves multiple functions: it generates the switching signal for the charge pump, senses the load current through its inherent characteristics, and regulates its own frequency based on the load conditions. The current mirror circuit is integrated into the existing oscillation circuitry, allowing the same circuit elements to perform both oscillation and current sensing functions, thereby minimizing additional complexity.
Solution Approach 2:
The patent merges the current sensing function with the oscillation circuit by using the oscillating signal itself to sense the load current. The frequency regulation is integrated into the oscillation generation process, where the load current directly influences the oscillation frequency through the current mirror. This consolidation eliminates the need for separate sensing and control circuits, reducing overall device complexity while maintaining voltage stability.
Data Source
AI summary
An apparatus for controlling a charge pump includes a current sensor arranged to output a current sense signal that is linearly proportional to an output current of the charge pump, and an oscillator that provides a clock signal for the charge pump. The oscillator receives the current sense signal and uses it to vary an oscillation frequency of the clock signal. An amplitude of the clock signal also may be varied in response to the current sense signal.