Multi-mode Charge Pump with Shared Flyback Capacitor
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Solution Overview
Problem
Conventional charge pumps are inefficient and costly for mobile communications devices, unable to generate multiple voltage reference levels required by components like Class-G amplifiers, and suffer from fixed turn-on resistance issues that cause output voltage variations and instability.
Innovation Solution
A power-efficient multi-mode charge pump with dynamic turn-on resistance control and smooth mode transition, utilizing a charge pump stage with shared flyback capacitors and MOSFET switches, and a regulation circuit that provides clocked control signals to manage switching groups and transition between full-voltage and half-voltage modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional charge pump uses a small fixed turn-on resistance to maintain stable output voltage at high load currents, then output voltage stability is improved, but the switch becomes unreliable in the presence of large charge current from a high voltage power source
Solution Approach 1:
The patent applies dynamic resistance control by adjusting the turn-on resistance of switches based on operating conditions. The resistance is dynamically modified during mode transitions and across different voltage modes (full-voltage and half-voltage) to optimize both stability and reliability. This is achieved through control circuits that adjust switch parameters in real-time based on load current and power source conditions.
2Stability of the object's composition
If a conventional charge pump uses a small fixed turn-on resistance to maintain stable output voltage, then output voltage stability is improved, but large output voltage variations occur at low load currents
Solution Approach 1:
The patent implements dynamic resistance adjustment that adapts to load conditions. At low load currents, the turn-on resistance is increased to prevent excessive voltage variations, while at high load currents, it is decreased to maintain stability. This dynamic adaptation is achieved through control circuits that monitor load conditions and adjust switch parameters accordingly, resolving the contradiction between stability and precision across different operating points.
3Adaptability or versatility
If multiple conventional charge pumps are used to generate multiple voltage reference levels, then voltage level requirements are met, but device complexity and cost increase
Solution Approach 1:
The patent implements a single multi-mode charge pump that can generate multiple voltage reference levels (full-voltage mode and half-voltage mode) by reconfiguring its internal circuitry. The charge pump uses switching groups and mode selection logic to provide different voltage outputs from a single device, eliminating the need for multiple separate charge pumps and reducing overall system complexity while maintaining versatility.
4Device complexity
If a single conventional charge pump is used to generate multiple voltage reference levels, then device complexity is reduced, but the charge pump becomes unreliable during mode transitions
Solution Approach 1:
The patent implements preliminary action by preparing the charge pump for mode transitions in advance. Before transitioning between full-voltage and half-voltage modes, the control circuit pre-configures the switching groups and adjusts parameters to ensure a smooth, reliable transition. This prevents instability and reliability issues during mode changes by preparing the system beforehand rather than reacting after problems occur.
Data Source
AI summary
Disclosed is a power-efficient multi-mode charge pump. The charge pump comprises a first pumping circuit that provides at least one output voltage produced by a discharge sequence of a shared flyback capacitor. The charge pump also comprises a second pumping circuit that provides a plurality of output voltages produced by a corresponding plurality of discharge sequences of the shared flyback capacitor. The charge pump may include a transition circuit to selectably enable the first pumping circuit or the second pumping circuit. In one embodiment, the first pumping circuit may employ a two-phase discharge sequence. In another embodiment, the second pumping circuit may employ a three-phase plurality of discharge sequences. A related method is also disclosed.