Charge-Based Charge Pump Wide Output Voltage Range
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Solution Overview
Problem
Conventional charge pumps in frequency synthesizers face limitations due to inherent nonlinearities, restricted output voltage range, and increased complexity, which affect their performance and power consumption, especially in wide tuning range applications.
Innovation Solution
A charge-based charge pump architecture that extends the output voltage range from −0.84·VDD to 1.82·VDD, utilizing a digital logic circuit to control NMOS and PMOS devices, dynamic and static body-bias generators, and charge transfer subcircuits to achieve a wide and linear output voltage range while minimizing memory effects and shoot-through current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current mirror charge pump is used, then linear characteristics and low noise performance are achieved, but output voltage range is restricted to less than 70% of VDD and complexity increases due to high-gain auxiliary feedback loop
Solution Approach 1:
The patent extracts and removes the complex high-gain auxiliary feedback loop from the conventional current mirror charge pump, replacing it with a simplified charge-based architecture that achieves similar linear characteristics without the additional complexity. The feedback mechanism is fundamentally changed from voltage-based high-gain amplification to charge-based direct control.
Solution Approach 2:
The patent substitutes the voltage-based feedback mechanism (analog/mechanical system) with a charge-based control mechanism. Instead of using high-gain voltage amplification to maintain linearity, the invention directly controls charge transfer amounts, replacing the complex voltage feedback system with a simpler charge-domain control approach.
2Manufacturing precision
If cascoding is implemented in constant current branches, then current matching is improved, but output voltage range and minimum supply voltage are further restricted
Solution Approach 1:
The patent replaces the voltage-based cascoding structure with a charge-based control mechanism. Instead of using stacked transistors to achieve current matching, the invention directly controls the charge transfer amount through capacitor discharge, eliminating the need for cascoding and its associated voltage headroom requirements.
Solution Approach 2:
The patent changes the control parameter from voltage (in conventional current mirror CP) to charge amount. By controlling the charge transfer quantity directly through capacitor discharge rather than through voltage-based current mirrors, the system achieves precise control without the voltage restrictions imposed by cascoding structures.
3Use of energy by stationary object
If charge-based charge pump is used, then power consumption is reduced and matching performance is improved, but useable linear output voltage range becomes even lower
Solution Approach 1:
The patent changes the fundamental operating parameter from voltage-based control to charge-based control. By measuring and controlling the charge transfer amount directly rather than inferring it from voltage changes, the system can achieve accurate control over a wider output voltage range while maintaining low power consumption characteristics.
Solution Approach 2:
The patent implements a feedback mechanism that measures the actual charge transfer amount and uses this information to control subsequent charge transfers. This feedback approach enables the system to maintain accurate control and linearity across an extended output voltage range, overcoming the limitation of conventional charge-based CPs.
4Adaptability or versatility
If wide output voltage range is achieved, then application versatility is improved, but ripple magnitude and memory effects may increase
Solution Approach 1:
The patent employs a feedback mechanism that measures the charge transfer amount and uses this information to compensate for variations and maintain consistent performance across the wide output voltage range. This feedback control suppresses ripple and eliminates memory effects by ensuring each charge transfer is precisely controlled regardless of the operating point.
Solution Approach 2:
The patent changes from voltage-based operation to charge-based operation, where the fundamental control variable is the charge amount transferred. This parameter change enables wide output voltage swing while maintaining consistent transfer characteristics, as the charge transfer quantity is directly controlled rather than being dependent on voltage headroom.
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 proposed charge pump achieves a wide and linear output voltage range with minimal ripple, independent of prior states, enabling efficient operation in wide tuning range applications with reduced power consumption and complexity.
Implementation Method 1
the charge from pump capacitor, nominally charged to VDD, is shared to the load capacitor, following the trigger input by the incoming UP/DN pulse inputs. This capacitive charge re-distribution scheme results in improved matching performance
Data Source
AI summary
A charge-based charge pump with wide output voltage range is provided. In the charge-based charge pump, the digital logic circuit is configured to receive an up pulse signal and a down pulse signal and output a plurality of switching signals for controlling the first NMOS, the positive hold subcircuit, the first dynamic body-bias generator, the positive charge transfer subcircuit, the first static body-bias generator, the first PMOS, the negative hold subcircuit, the second dynamic body-bias generator, the negative charge transfer subcircuit and the second static body-bias generator electrically connected therewith, so as to allow the output voltage to range from −0.84·VDD to 1.82·VDD. The charge-based charge pump is triggered by the up or down pulse signal or works in a default state, and the top plate and the bottom plate of the pump capacitor are electrically connected to different node and terminal according to the plurality of switching signals.