Analog H-Bridge Driver for Bi-Directional TEC Power Control
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Solution Overview
Problem
Existing bi-directional drivers for thermo-electric coolers (TECs) require complex digital circuits and large inductance to convert PWM signals to DC, making them inefficient and cumbersome.
Innovation Solution
A bi-directional driver with an H-bridge configuration utilizing non-inverting and inverting amplifiers to control high and low side transistors, allowing for analogue operation by adjusting the control signal's critical reference, enabling efficient PWM control without the need for large inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PWM control is used to drive the TEC, then the power supplied to the TEC can be adjusted, but complicated digital circuits and large inductance are required to convert the pulsed signal into a DC signal
Solution Approach 1:
The patent replaces the conventional PWM control mechanism (which requires digital circuits and large inductance for pulse-to-DC conversion) with an analogue voltage control system. The H-bridge driver uses operational amplifiers to directly convert the control voltage into proportional output voltages, eliminating the need for PWM frequency generation, digital logic circuits, and large filtering inductors. This substitution of the control mechanism fundamentally reduces circuit complexity while preserving power adjustment capability.
Solution Approach 2:
The patent changes the control parameter from digital PWM duty cycle to analogue control voltage level. By using operational amplifiers in non-inverting and inverting configurations, the system directly translates control voltage magnitude into output power level, eliminating the intermediate pulse generation and filtering stages required by PWM methods. This parameter transformation simplifies the control pathway and reduces component requirements.
2Adaptability or versatility
If conventional H-bridge PWM driver is used, then bi-directional control is achieved, but the circuit requires large inductance to convert pulsed signal to DC signal
Solution Approach 1:
The patent substitutes the PWM pulse generation and filtering mechanism with direct analogue voltage control. The operational amplifiers generate continuous analogue output voltages that directly drive the TEC in both directions, eliminating the need for large inductors that would be required to filter PWM pulses into DC. The bi-directional control is achieved through the inherent capability of the H-bridge configuration controlled by analogue voltages, maintaining functionality while removing the inductance requirement.
Solution Approach 2:
The patent extracts and removes the inductance component from the system by replacing PWM control with analogue control. The large inductor that would be necessary for pulse-to-DC conversion in PWM systems is completely eliminated, as the operational amplifier-based H-bridge driver directly produces the required bidirectional current without needing pulse filtering.
3Adaptability or versatility
If PWM control with digital circuits is used, then power adjustment is achieved, but the control circuitry becomes complicated
Solution Approach 1:
The patent replaces the digital PWM control system with an analogue control system based on operational amplifiers. The control voltage directly modulates the H-bridge output through the operational amplifiers' voltage amplification and inversion capabilities, eliminating digital logic circuits, frequency generators, and pulse width modulation circuitry. This analogue approach maintains full power control capability while dramatically simplifying the control circuit architecture.
Solution Approach 2:
The operational amplifier-based control system performs multiple functions simultaneously: it provides voltage amplification, signal inversion for bidirectional control, and direct drive capability for the H-bridge. This multi-functional analogue approach replaces what would otherwise require separate digital circuits for PWM generation, timing, and control logic, consolidating control functions into a simpler universal analogue control mechanism.
Data Source
AI summary
An H-bridge driver without implementing with the PWM mode is disclosed. The H-bridge driver of the invention includes a non-inverting amplifier and an inverting amplifier commonly connected to the control signal. When the control signal exceeds the reference, the non-inverting amplifier commonly drives the first pair of transistors diagonally connected to the load. The low side transistor fully turns on but the high side transistor linearly operates. When the control signal is less than the reference, the inverting amplifier commonly drives the second pair of transistors also diagonally connected to the load.