Negative Charge Pump for P-Channel Device Gate Drive
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Solution Overview
Problem
P-channel devices face challenges in achieving low on-resistance (RDSON) across varying voltage conditions due to conflicting trade-offs, such as high RDSON at low voltages and junction leakage at high voltages, limiting their suitability for a wide range of systems.
Innovation Solution
A negative charge pump is used to maintain an optimal gate drive voltage for p-channel devices, allowing for reduced RDSON without increasing device size or limiting voltage range, by creating a negative voltage potential below ground and facilitating increased gate drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a high voltage p-channel device is selected for low voltage operation, then the device can operate across a wide voltage range, but the on-resistance (RDSON) becomes high due to insufficient gate drive voltage
Solution Approach 1:
A negative charge pump circuit is introduced as an intermediary component to generate the additional negative gate drive voltage required. The charge pump converts the available supply voltage into a more negative gate voltage, enabling the p-channel device to operate with optimal drive voltage even when the supply voltage is insufficient.
Solution Approach 2:
The gate voltage parameter is dynamically changed by the charge pump circuit. Instead of relying on the supply voltage directly, the gate voltage is transformed into a more negative value through the charge pump, thereby changing the electrical parameter to achieve lower on-resistance while maintaining compatibility with high voltage rating devices.
2Reliability
If a low voltage p-channel device is selected to improve on-resistance, then the RDSON decreases, but the device exhibits higher channel and junction leakage and is limited to a narrow voltage range
Solution Approach 1:
The negative charge pump acts as a mediator that allows high voltage p-channel devices to operate at low supply voltages by providing the necessary gate drive. This enables the use of devices with higher voltage ratings without being constrained by the supply voltage, thereby expanding the usable voltage range while maintaining low on-resistance.
Solution Approach 2:
Instead of selecting a low voltage device to reduce on-resistance, the invention inverts the approach by selecting a high voltage device and using a charge pump to create the appropriate gate drive conditions. This reversal allows utilization of devices with better leakage characteristics while achieving the desired low on-resistance performance.
3Reliability
If the p-channel device area is increased to reduce on-resistance, then the RDSON decreases, but the device footprint becomes larger
Solution Approach 1:
The electrical parameter (gate voltage) is changed through the charge pump circuit rather than changing the physical parameter (device area). By providing enhanced negative gate drive voltage, the existing device area is utilized more effectively to achieve lower on-resistance, avoiding the need to increase the device footprint.
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 approach enables p-channel devices to maintain low RDSON across a wide operating voltage range without increasing device size, avoiding junction and channel leakage, and allowing for higher threshold voltage usage.
Implementation Method 1
A negative charge pump is used to maintain an optimal gate drive voltage for p-channel devices
Data Source
AI summary
A technique for enhancing the conduction of a p-channel device is disclosed. Specifically, a negative charge pump is configured to provide a gate drive voltage to a p-channel device. The negative charge pump creates a negative voltage potential below ground and facilitates increased gate drive for the p-channel device. The gate drive voltage output by the negative charge pump may be selected such that it is optimal for the p-channel device operation.