Charge Pump Commutation Timing for Voltage Multiplication
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Solution Overview
Problem
Charge pumps face inefficiencies in multiplying DC operating voltage, particularly due to the requirement for multiple stages and the need for precise control of commutation times to optimize output voltage generation.
Innovation Solution
A charge pump design with a control and regulation unit that specifies commutation times based on minimum and maximum time periods and threshold values, allowing for efficient generation of output voltage by integer or fractional multiplication of the DC operating voltage, using a buffer capacitor and tap changers connected via phase-shifted charging voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple pump stages are cascaded to multiply the DC operating voltage, then the output voltage multiplication capability is improved, but the chip area required increases
Solution Approach 1:
The patent employs periodic commutation of charging voltages with alternating rising and falling sections to transfer charge packets to the buffer capacitor at optimized intervals. This periodic action allows voltage multiplication through time-based sequencing rather than requiring proportionally more physical stages, reducing the chip area needed for a given multiplication factor.
Solution Approach 2:
The control and regulation unit dynamically adjusts commutation times based on threshold values of charging voltages and voltage drops across tap changers. This dynamic timing optimization allows the charge pump to achieve efficient voltage multiplication with fewer stages by adapting the charging rhythm to actual circuit conditions, thereby reducing required chip area.
2Measurement precision
If commutation times are extended to ensure complete charge transfer, then the output voltage accuracy is improved, but the operating speed decreases
Solution Approach 1:
The control and regulation unit monitors threshold values of charging voltages and voltage drops across tap changers in real-time, using this feedback to determine optimal commutation moments. This feedback mechanism ensures commutation occurs at precisely the right moment to complete charge transfer for accurate output voltage while maintaining high operating speed by avoiding unnecessarily extended commutation periods.
Solution Approach 2:
The patent changes the timing parameters dynamically by specifying commutation times based on measured voltage thresholds rather than using fixed time intervals. This parameter adaptation allows the system to achieve both high accuracy (by waiting for complete charge transfer indicated by threshold crossing) and high speed (by not waiting longer than necessary).
3Area of stationary object
If the number of pump stages is reduced to decrease chip area, then the chip area requirement is reduced, but the output voltage multiplication capability deteriorates
Solution Approach 1:
By implementing periodic commutation with alternating charging phases and utilizing a buffer capacitor that accumulates charge over multiple cycles, the system achieves voltage multiplication with fewer physical stages. The periodic charging and discharging of capacitors through controlled commutation enables the same multiplication effect that would traditionally require more stages, thus reducing chip area.
Solution Approach 2:
The control unit prepares commutation signals in advance based on predicted threshold crossings, and the buffer capacitor pre-stores charge during charging phases. This preliminary preparation allows fewer pump stages to achieve the required output voltage by maximizing the utilization of each stage's charging capability rather than requiring additional stages.
4Speed
If commutation frequency is increased to improve operating speed, then the operating speed is improved, but electromagnetic interference emissions increase
Solution Approach 1:
The system uses periodic commutation with carefully controlled duty cycles and alternating phases that can be optimized to reduce harmonic content in the switching signals. By structuring the periodic action with balanced rising and falling sections and utilizing the buffer capacitor to smooth current transitions, the charge pump achieves high operating speed while minimizing electromagnetic interference through inherent filtering effects of the capacitive structure.
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
This design enhances the efficiency of charge pumps by optimizing commutation times, reducing chip area requirements, and minimizing electromagnetic interference (EMI) emissions, while maintaining high output voltage accuracy.
Implementation Method 1
a buffer capacitor (32), which is connected to the at least one pump stage via a further switch and across which the output voltage is present
Implementation Method 2
The multiplication of the supply voltage V SUP takes place by cascading diodes and capacitors, with each pump stage 12,14,16 usually having two tap changers 18,20 and pump capacitors 22,24
Data Source
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AI summary
The charge pump (10) for generating an output voltage by multiplying a DC operating voltage is equipped with at least one pump stage, which includes at least one pump capacitor and at least one tap changer and is connected between the DC operating voltage (VSUP) and a charging voltage. The charging voltage exhibits a time profile with alternating rising and falling time periods, each beginning at commutation times.A control and regulation unit (34) generates the at least one charging voltage and specifies the commutation times for the commutation of the at least one charging voltage, according to at least one of the three conditions listed below: - upon the expiry of a predefinable minimum time interval (tMIN) from the last commutation time, - upon the expiry of a predefinable maximum time interval (TMAX) from the last commutation time, or - upon reaching predefinable maximum and minimum threshold values of the at least one charging voltage within its rising or falling time intervals, provided that the respective threshold value is reached within a time interval beginning with the last commutation time that ends later than the minimum time interval (tMIN) and earlier than the maximum time interval (TMAX).