Active Charge Pump Circuit for PSRAM Voltage Generation
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Solution Overview
Problem
Circuit elements in voltage generators for pseudo static random access memory (PSRAM) systems are prone to damage and instability due to high operation voltages and threshold voltage variance caused by the body effect, leading to increased power consumption and reliability issues.
Innovation Solution
An active charge pump circuit is introduced, comprising a charge pump circuit, control circuit, and charge transfer circuit with PMOS transistors, which generates a charge pumping voltage and outputs an active voltage varying between a ground voltage and a boosted power supply voltage, twice that of the power supply voltage, thereby reducing the body effect and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high operation voltages are used in voltage generator circuit elements, then the active mode voltage requirement is met, but circuit elements are damaged and reliability decreases
Solution Approach 1:
The voltage generation system is divided into two separate circuits: a standby charge pump circuit operating at low voltage (VCC) and an active charge pump circuit operating at high voltage (2×VCC). This segmentation allows each circuit to operate within safe voltage ranges for its specific function, preventing damage to circuit elements while still providing the required high voltage during active mode.
Solution Approach 2:
The system dynamically switches between two charge pump circuits based on operational mode. The standby charge pump circuit operates during standby mode, and the active charge pump circuit operates during active mode. This dynamic switching enables the system to use appropriate voltage levels for each mode, avoiding high voltage damage during standby while meeting high voltage requirements during active operation.
2Power
If high operation voltages are used in voltage generator circuit elements, then the active mode voltage requirement is met, but circuit elements operate unstably due to threshold voltage variance
Solution Approach 1:
The voltage generation functionality is segmented into two separate charge pump circuits with different operating voltage characteristics. The standby charge pump uses low voltage (VCC) operation which provides stable threshold voltages, while the active charge pump handles high voltage (2×VCC) requirements. This segmentation isolates the stability-critical circuitry from high voltage variations.
Solution Approach 2:
The control circuit acts as an intermediary that manages the switching between standby and active charge pump circuits. It receives the active enable signal and appropriately activates the correct charge pump circuit, ensuring that threshold voltage stability is maintained by keeping control circuitry operating at stable low voltages while allowing the power delivery circuit to handle high voltages.
3Power
If voltage generator circuit elements are designed for high voltage operation, then active mode voltage is provided, but power consumption increases
Solution Approach 1:
The system dynamically activates only the necessary charge pump circuit based on operational mode. During standby mode, only the low-power standby charge pump operates. During active mode, the active charge pump is activated to provide the required high voltage. This dynamic operation reduces overall power consumption by avoiding continuous high-voltage operation.
Solution Approach 2:
The system discards the use of high-voltage circuitry during standby mode when it is not needed, and recovers by activating it only during active mode when high voltage is required. This on-demand activation of high voltage circuitry minimizes power consumption while ensuring voltage requirements are met when needed.
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 active charge pump circuit improves the reliability and power efficiency of voltage generation, reducing power consumption and stabilizing the active voltage output, while protecting circuit elements from high voltage damage.
Implementation Method 1
The charge pump circuit generates a charge pumping voltage in response to an active enable signal
Implementation Method 2
The charge transfer circuit outputs the charge pumping voltage as an active voltage in response to the charge transfer control signal
Data Source
AI summary
An active charge pump circuit may include a charge pump circuit, a control circuit, and a charge transfer circuit. The charge pump circuit may generate a charge pumping voltage in response to an active enable signal. The control circuit may generate a charge transfer control signal varying between a ground voltage and a boosted power supply voltage that is twice as much as a power supply voltage in response to the active enable signal. The charge transfer circuit may output the charge pumping voltage as an active voltage in response to the charge transfer control signal.