Charge Pump Circuit Dynamic Current Control for Noise Reduction
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Solution Overview
Problem
Conventional charge pump circuits face issues with noise generation and excessive current supply due to constant current settings, leading to inefficiencies and increased power source noise, especially when the current consumed by the video amplifier varies.
Innovation Solution
A charge pump circuit with supply current amount control means that adjusts the current supplied to a capacitor based on the current flowing through the driven circuit, ensuring a positive correlation between the supply current and the load current, thereby reducing noise and optimizing current usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant current is used to accumulate electric charges in the capacitor, then the charge pump circuit can operate reliably even when the current consumed by the video amplifier is large, but a current larger than necessary flows within a normal use range, causing increased power source noise
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant current source to a dynamic current source that adjusts its output based on the video amplifier's current consumption. The control circuit monitors the current consumed by the video amplifier and dynamically adjusts the charging current of the capacitor accordingly, ensuring the current matches the actual demand rather than maintaining a fixed high value for all conditions.
Solution Approach 2:
The patent implements feedback by using a control circuit that monitors the current consumed by the video amplifier and uses this information to adjust the charging current of the capacitor. This closed-loop feedback mechanism ensures that the charging current is optimized based on actual load conditions, preventing excessive current flow and reducing power source noise while maintaining operational reliability.
2Power
If a large constant current is supplied to the capacitor, then the charge pump circuit can meet the current demand during high consumption periods, but excessive current flows during normal use, reducing energy efficiency
Solution Approach 1:
The patent applies dynamics by making the charging current adaptive rather than static. The control circuit continuously adjusts the charging current based on the video amplifier's actual current consumption, allowing the system to supply high current when needed while reducing current during normal operation, thus optimizing energy efficiency without sacrificing power supply capability.
Solution Approach 2:
The patent changes the parameter of charging current from a fixed constant value to a variable value that changes according to the load conditions. By monitoring the video amplifier's current consumption and adjusting the charging current parameter dynamically, the system achieves both high power supply capability during peak demand and energy efficiency during normal operation.
3Object-generated harmful factors
If the charging current is reduced to minimize noise, then power source noise is reduced, but the charge pump circuit may not have sufficient current supply capability when the video amplifier consumes large current
Solution Approach 1:
The patent resolves this contradiction by making the charging current dynamic rather than static. The control circuit adjusts the charging current in real-time based on the video amplifier's current consumption, allowing the system to use low current during normal operation to minimize noise while automatically increasing current supply capability when the video amplifier demands high current, thus eliminating the need to choose between noise reduction and power capability.
Data Source
AI summary
Provided is a charge pump circuit which is preferably used for reducing noise generated when electric charges are accumulated in a capacitor of the charge pump circuit. A load driving system 1 includes a charge pump circuit 2, a clock generation circuit 4, an amplifier circuit 6, and a load 8. The charge pump circuit 2 includes capacitors C1 and C2, a transistor PTr3 which is a P-channel MOS transistor and controls current supply to the C1, switching elements SW1 to SW3, and a supply current control circuit 20. The charge pump circuit 2 switches the SW1 to SW3, to thereby perform the accumulation of electric charges to the C1 and the transfer of the accumulated electric charges to the C2 for generating a negative power source. The supply current control circuit 20 includes a transistor PTr4, a switching element SW4, and a transistor NTr6 which forms a current mirror with a transistor NTr5 which constitutes an output stage of the amplifier circuit 6. The C1 is charged with a supply current which is positively correlated with a load current via the NTr6, the SW4, the PTr3, and the PTr4.