Regulated Charge Pump for Extended Back Bias in FDSOI
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Solution Overview
Problem
Existing semiconductor technologies face challenges in generating extended forward back biasing for PMOS devices, particularly in Fully Depleted Silicon-On-Insulator (FDSOI) technology, where conventional charge pumps are limited in back bias range and require complex calibration and reference signals.
Innovation Solution
A regulated charge pump with a sense circuit that provides a level-shifted positive feedback voltage proportional to the negative output voltage, eliminating the need for reference currents or voltages and switch control, and capable of handling voltages higher than the supply voltage, using a voltage-to-current converter and current mirror configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional charge pumps are used to generate back bias voltage, then the circuit can operate with standard components, but the back bias range is limited and calibration is required
Solution Approach 1:
The patent implements a feedback mechanism where the negative output voltage from the charge pump is fed back through a sense circuit to a voltage-to-current converter. This converter generates a control current that regulates the charge pump operation, enabling the circuit to automatically adjust and maintain the desired back bias range without external calibration. The feedback loop continuously monitors the output and adjusts the pumping action accordingly.
Solution Approach 2:
The invention changes the operating parameters of the charge pump by using a voltage-to-current converter that transforms the negative voltage output into a proportional current signal. This current then controls the switching elements within the charge pump, dynamically adjusting its operation to achieve extended back bias ranges. The parameter transformation from voltage to current enables new operating modes that were not accessible with conventional voltage-controlled approaches.
2Reliability
If reference currents and voltages are used for regulation, then the charge pump can be controlled, but additional power consumption and circuit complexity increase
Solution Approach 1:
The sense circuit utilizes the negative output voltage from the charge pump itself as the input signal for regulation. Instead of requiring external reference voltages or currents, the circuit self-regulates by feeding back its own output through the voltage-to-current converter. This self-service approach eliminates the need for separate reference generation circuits, reducing both power consumption and circuit complexity while maintaining regulation accuracy.
3Reliability
If switch control circuits are added to the feedback path, then the charge pump can be regulated, but the circuit complexity and power consumption increase
Solution Approach 1:
The patent extracts the essential regulation function from complex switch control circuits and implements it through a voltage-to-current converter. By removing the traditional switch-based feedback control and replacing it with a continuous current signal generated from the negative voltage, the invention eliminates the need for additional control switches in the feedback path. This extraction of the core regulation mechanism simplifies the feedback path while maintaining effective charge pump control.
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
Enables efficient extended forward back biasing in FDSOI technology, maximizing battery lifetime and compensating for process variations without requiring calibration or additional power consumption, while maintaining a compact design.
Implementation Method 1
a voltage-to-current converter coupled to the negative charge pump output and configured to convert the negative charge pump output to a proportional current
Implementation Method 2
a current mirror coupled to the voltage-to-current converter and configured to mirror the proportional current to a level-shifted positive feedback voltage signal
Data Source
AI summary
A circuit includes first, second, and third power supply terminals. The circuit includes an input node coupled to receive a negative voltage and an output node coupled to provide a positive voltage proportional to the negative voltage. The circuit includes a voltage-to-current converter coupled to the first power supply terminal and the input node and configured to generate an intermediate current proportional to the negative voltage at the input node. The circuit also includes a current mirror coupled to the second power supply terminal and third power supply terminal and configured to mirror the intermediate current through a first resistor to provide the positive proportional voltage.