High-Frequency Oscillator Circuit with Miller Capacitance Control
Here’s PatSnap Eureka !
Summary
Problems
Conventional oscillator circuits using comparators fail to follow relatively high-frequency control signals due to the time required to charge and discharge the Miller capacitance between the gate and drain of MOSFETs, leading to oscillation failure.
Innovation solutions
Incorporating a charge-discharge control unit and an output control unit in the comparator circuit, which includes inverters, logic circuits, and transistors to control the charge-discharge of Miller capacitance and adjust the output of the gain unit, allowing the comparator to follow high-frequency control signals.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a conventional comparator circuit is used, then the circuit structure is simple, but the circuit cannot follow high-frequency control signals due to Miller capacitance charging time
Why choose this principle:
The comparator circuit is segmented into distinct functional units: a differential unit for voltage comparison and a gain unit for signal amplification. The gain unit includes a first gain circuit with a first MOSFET and a second gain circuit with a second MOSFET, allowing independent optimization of each stage's response characteristics while managing Miller capacitance effects separately
Principle concept:
If a conventional comparator circuit is used, then the circuit structure is simple, but the circuit cannot follow high-frequency control signals due to Miller capacitance charging time
Why choose this principle:
A compensation capacitor is introduced as an intermediary element connected between the gate and drain of the MOSFETs in the gain unit. This capacitor actively manages the Miller capacitance effect by providing a controlled discharge path, enabling the circuit to follow high-frequency control signals without excessive complexity in the overall architecture
Application Domain
Data Source
AI summary:
Incorporating a charge-discharge control unit and an output control unit in the comparator circuit, which includes inverters, logic circuits, and transistors to control the charge-discharge of Miller capacitance and adjust the output of the gain unit, allowing the comparator to follow high-frequency control signals.
Abstract
Oscillator circuit uses a comparator, and controls charge-discharge of Miller capacitance between gate and drain of a MOSFET serving as an amplifier of the comparator gain unit and gate capacitance of the MOSFET, and enables comparator output to follow a high-frequency control signal that is input externally. An oscillator circuit uses a comparator CMP having differential and gain units. This oscillator circuit includes: a charge-discharge controller to control charge-discharge of Miller capacitance between gate and drain of a MOSFET and gate capacitance of the MOSFET; and an output controller to control output of the gain unit. Output controller includes: an inverter to connect to an input of the differential unit and receive a control signal input; a logic circuit to receive output of the inverter and output of the gain unit as an input; a transistor; and a capacitor to connect to input and output of the logic circuit.