MOS Gate Drive Circuit Using Antenna Rectification for Low-Power LF Receivers
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Solution Overview
Problem
Conventional low frequency (LF) receivers for remote keyless entry (RKE) systems face challenges in generating high gate drive voltage efficiently, especially in low power designs where voltage multipliers consume significant current, affecting the accuracy and sensitivity of localization due to unknown spatial orientation of the key fob.
Innovation Solution
A gate drive circuit that charges the switching transistor's gate to a sufficient voltage using a ground rectifier switch, diode, and capacitors, allowing fully differential connection with the antenna, reducing current consumption and enabling operation with low voltage power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage multiplier (charge pump) is used to generate high gate drive voltage, then the MOS switch can be properly turned on, but significant current is consumed which is not feasible for extremely low power design
Solution Approach 1:
Instead of using a conventional voltage multiplier that steps up voltage from a low voltage supply, the patent inverts the approach by using the antenna's natural high voltage RF signal to directly charge the gate of the MOS switch through a rectifier circuit. This eliminates the need for a battery-powered voltage multiplier and its associated high current consumption, achieving both reliable MOS switch operation and extremely low power consumption.
2Reliability
If a high gate drive voltage is needed to turn on the MOS switch, then the switching performance is improved, but the power supply voltage requirement increases which conflicts with low voltage battery operation
Solution Approach 1:
The patent changes the voltage parameter source from a fixed low voltage battery supply to a variable high voltage RF signal from the antenna. By rectifying the RF signal, the gate drive voltage dynamically follows the RF signal amplitude, automatically adapting to provide sufficient voltage for MOS switch turn-on without requiring a high voltage power supply or voltage multiplier circuit.
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 solution enhances the sensitivity of LF receivers, allows for low power operation without extra current consumption, and facilitates fully integrated trimming circuits, improving the overall performance of LF receivers.
Implementation Method 1
A gate drive circuit is disclosed that charges the gate of a switching transistor to a voltage that is high enough to turn the transistor fully on
Implementation Method 2
then prevent the charge from flowing back into the gate drive circuit
Data Source
AI summary
A gate drive circuit is disclosed that charges the gate of a switching transistor to a voltage that is high enough to turn the switching transistor fully on and then prevent the charge from flowing back into the gate drive circuit. The gate drive circuit works with a ground rectifier switch by providing a fully differential connection of the switching transistor and its capacitor and resistor in parallel with the antenna.