Charge Pump Ramp Rate Control Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Charge pumps in integrated circuits face challenges in maintaining a stable output voltage and controlling ramp rates, leading to potential latch-up conditions and inefficiencies, especially when handling significant load currents or varying voltage requirements.
Innovation Solution
Incorporating voltage regulation and ramp rate control circuitry using comparator circuits, a current source, and capacitors to maintain a target output voltage and limit the maximum permissible ramp rate, preventing excessive voltage changes and ensuring stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge pump is made strong enough to handle large load currents, then it can operate satisfactorily under a wide variety of load conditions, but the output voltage changes too rapidly causing circuitry to malfunction
Solution Approach 1:
A ramp rate control circuit is introduced as an intermediary between the charge pump output and the controlled circuitry. This circuit includes a capacitor that integrates the charge pump output, producing a smoothed version with limited ramp rate. The control circuit monitors the voltage across the capacitor and adjusts the charge pump operation to prevent excessive voltage changes, thereby protecting downstream circuitry while maintaining reliable operation under various load conditions.
2Stability of the object's composition
If voltage regulation circuitry is added to maintain target output voltage, then voltage stability is improved, but device complexity increases
Solution Approach 1:
The voltage regulation function is merged with the existing charge pump structure by integrating a control circuit that shares components with the charge pump's oscillating elements. The control circuit utilizes the charge pump's internal nodes and combines them with minimal additional components (comparators, capacitors, and control logic) to achieve voltage regulation. This merging approach maintains voltage stability while minimizing the increase in device complexity compared to a separate regulation system.
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 effectively regulates output voltage and controls ramp rates, preventing latch-up conditions and ensuring efficient operation under various load conditions, even with significant load currents, while optimizing power supply functions without excessive pin usage.
Implementation Method 1
The ramp rate control circuitry may have a current source and a capacitor. The current source may charge the capacitor to produce a ramping reference voltage.
Data Source
AI summary
A charge pump circuit is provided that has a controllable ramp rate. The charge pump circuit may receive a control signal from a control circuit. The control signal may be asserted by the control circuit to turn on the charge pump circuit. When the charge pump circuit is turned on, the charge pump circuit produces an output voltage. The output voltage ramps up from an initial value to a desired target value. During the ramp up process, a ramp rate regulation circuit monitors the output voltage and ensures that the ramp rate does not exceed a desired maximum value. A capacitor may be charged at a desired ramp rate to use as a time-varying reference voltage. A feedback circuit may be used to maintain the output voltage at the desired target value once the ramp-up process is complete.