Charge Pump Bias Circuits for Stable Low-Noise Voltage Generation
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Solution Overview
Problem
Existing bias signal generators struggle to provide stable voltage and current signals to variable load devices while minimizing energy consumption and noise introduction.
Innovation Solution
The proposed bias signal generation architecture includes a base bias signal generator module, differential oscillator module, positive and negative voltage charge pump modules, and clamping modules, which work together to efficiently generate and regulate stable bias signals, even with varying power supply conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing bias signal generators are used to provide stable voltage and current signals to variable load devices, then stable bias signals can be provided, but energy consumption increases and noise is introduced
Solution Approach 1:
The patent employs periodic switching action through charge pump circuits that operate in discrete phases (charging and discharging cycles). The switching elements (transistors M1-M4) periodically connect and disconnect capacitors C1-C2 to transfer charge, providing bias signals only when needed rather than continuous operation. This periodic action reduces average power consumption while maintaining signal stability during active periods.
Solution Approach 2:
The bias signal generator uses self-regulating feedback mechanisms where the output voltage stabilizes automatically through the interaction of the charge pump, capacitors, and load. The circuit self-adjusts the charging/discharging cycles based on load conditions, and the clamping diodes automatically prevent voltage excursions without external control, enabling the system to serve itself and maintain stability with minimal energy overhead.
2Reliability
If existing bias signal generators are used to provide stable voltage and current signals to variable load devices, then stable bias signals can be provided, but noise is introduced
Solution Approach 1:
The patent extracts and isolates noise-generating elements from the sensitive bias signal path. The charge pump switching operations, which generate noise, are separated from the output by using capacitors C1-C2 as energy storage elements that decouple the switching noise from the stabilized bias output. The clamping diodes D1-D2 further isolate voltage spikes and noise transients, allowing the main bias signal to remain clean while noise is extracted and contained in separate circuit elements.
3Loss of energy
If charge pump circuits are used to generate bias signals, then power consumption is reduced, but voltage regulation stability deteriorates
Solution Approach 1:
The patent incorporates capacitors C1 and C2 that are charged in advance during the charging phase of each cycle, storing energy before it is needed. These capacitors act as energy cushions that maintain voltage stability during the discharging phase and between switching cycles. By preparing energy storage beforehand, the circuit cushions against voltage drops and maintains regulation stability without requiring continuous high-power operation.
Solution Approach 2:
The bias signal generator implements implicit feedback through the load connection where the output voltage directly influences the charging/discharging behavior. When output voltage drops, the charge pump automatically increases charging current to restore it; when voltage rises, charging slows down. The clamping diodes provide voltage threshold feedback, preventing over-voltage conditions. This feedback mechanism maintains stability while keeping the charge pump operating at low average power.
Data Source
AI summary
An apparatus for generating a steady state positive voltage (PVS) signal and a steady state negative voltage (NVS) signal is presented. The apparatus includes a bias signal generation module for generating a steady state reference voltage signal (RVS) based on a varying supply voltage signal (VDD), the RVS having a voltage level less than the PVS. The apparatus further includes a positive signal generation module (PSGM) generating the PVS, the PSGM including a first capacitor, the PSGM employing the first capacitor to generate a portion of the PVS based on the RVS. The apparatus further includes a negative signal generation module (NSGM) generating the NVS, the NSGM including a second capacitor, the NSGM employing the second capacitor to generate a portion of the NVS based on the RVS.