Capacitive Voltage Regulator for Charge Pump Leakage Mitigation
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Solution Overview
Problem
Voltage regulators for charge pumps in memory units face issues with voltage drift due to current leakage and parasitic capacitance, which are difficult to mitigate without increasing capacitor size and cost.
Innovation Solution
A voltage regulator design that uses a capacitive voltage divider with a comparator and a series of switches to maintain the sampling node at a reference voltage during both reset and sampling modes, minimizing the impact of parasitic capacitance and current leakage, and allowing for compact and cost-efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the capacitance of first and second capacitors is increased to reduce the influence of parasitic capacitance, then the measurement precision is improved, but the device complexity and manufacturing cost increase due to bulky capacitors
Solution Approach 1:
The patent applies preliminary action by resetting the sampling node to a defined reference voltage level before each sampling operation through switch 3. This initialization ensures that the sampling node starts from a known state, eliminating the need for excessively large capacitors to maintain stability during reset transitions. The reset operation compensates for leakage effects without requiring bulky capacitance.
Solution Approach 2:
The patent implements periodic action by continuously performing reset operations at defined intervals before sampling phases. The sampling node is periodically reset to the reference voltage level, and this periodic resetting compensates for leakage effects that accumulate over time. This time-based approach replaces the need for large capacitors that would otherwise be required to maintain voltage stability without frequent resetting.
2Reliability
If a separate reset circuit is provided to reduce charge leakage from the sampling node, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the reset function with the existing capacitive divider structure by using switch 3 to directly connect the sampling node to the reference voltage source. Rather than adding a separate complex reset circuit with multiple components, the reset functionality is integrated into the existing capacitor network, sharing the reference voltage connection and minimizing additional circuitry.
Solution Approach 2:
The sampling node self-resets through the inherent reference voltage connection when switch 3 is activated. The capacitive divider structure itself provides the reset mechanism by reconnecting the sampling node to the stable reference voltage, eliminating the need for external reset circuits or additional active components to enforce voltage stability.
3Ease of operation
If switches are used to connect the sampling node to reference voltage for reset mode, then the ease of operation is improved, but current leakage across the switch influences the voltage on the sampling node
Solution Approach 1:
The patent applies preliminary action by performing the reset operation immediately before each sampling phase. Switch 3 is closed to connect the sampling node to the reference voltage, allowing leakage effects to be compensated during this preliminary reset phase. By resetting beforehand, the sampling operation starts from a known good state, and the brief duration of the reset connection minimizes the impact of switch leakage.
Solution Approach 2:
The patent rushes through the reset phase by using a brief, dedicated reset period before sampling. The switch 3 is closed only momentarily to reestablish the reference voltage level, and the sampling operation quickly follows. This rapid reset-sampling sequence minimizes the time during which switch leakage can affect the sampling node voltage, allowing the system to skip over the leakage problem rather than continuously fighting it.
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 solution effectively reduces voltage drift and maintains a stable high voltage output, minimizing the influence of parasitic capacitance and current leakage, enabling a compact and cost-efficient voltage regulator design.
Implementation Method 1
capacitive dividers are widely used, by way of which a high voltage level on the output of the charge pump can be sensed
Implementation Method 2
a high voltage level on the output of the charge pump can be sensed in the absence of any static current load. The capacitive divider is operable to divide the high voltage to levels which can be processed by a regulation or feedback loop that is typically operable to compare the downscaled voltage with a reference voltage
Implementation Method 3
Depending on this comparison, a voltage supply, typically in form of a charge pump is driven by the comparator to either increase or to decrease the voltage at the high voltage output
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a voltage regulator and to a method of operating a voltage regulator that is operable in a reset mode and in a sampling mode. The voltage regulator comprises : - a capacitive voltage divider (12) having a first capacitor (14) and a second capacitor (16) in series with the first capacitor, wherein the capacitive voltage divider is connectable to an output (30) of a voltage supply (28) to activate the sampling mode, - a comparator (20) having an output (26) connected to an input of the voltage supply, the comparator further having a first input (22) connected to a sampling node (18) arranged between the first capacitor and the second capacitor and the comparator having a second input (24) connected to a reference voltage (VREF), -wherein the sampling node is connectable to the reference voltage for activating the reset mode.