Signal Isolator Circuit for Single-Channel Multi-Signal Isolation
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Solution Overview
Problem
Existing power converters face challenges in efficiently transmitting multiple signals, including PWM and sigma-delta bit-streams, along with quasistatic status flags, across different ground levels without signal distortion or increased die size, particularly in power switching applications.
Innovation Solution
A modulator circuit and demodulator circuit are used to synchronize and encode multiple signals onto a single isolation channel using a predefined protocol, enabling efficient transmission of time-sensitive and non-time-dependent signals without distortion, utilizing a single isolation capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple isolation channels are used to transmit PWM, bit-stream, and status flags separately, then signal transmission reliability is improved, but die size increases
Solution Approach 1:
The patent combines multiple isolation channels into a single channel by time-division multiplexing. The modulator circuit transmits PWM signals, bit-streams, and status flags sequentially over one isolation capacitor using a single modulator-demodulator pair, eliminating the need for multiple parallel isolation channels while maintaining signal integrity and reducing die size.
Solution Approach 2:
The system uses periodic time-division multiplexing where different signal types are transmitted in alternating time slots. The modulator switches between transmitting PWM signals during first time periods and bit-streams/status flags during second time periods, allowing single-channel transmission of multiple signal types without interference.
2Measurement precision
If multiple modulator-demodulator pairs are used for different signal types, then signal transmission accuracy is improved, but device complexity increases
Solution Approach 1:
The single modulator-demodulator pair is designed to handle multiple signal types (PWM, bit-streams, status flags) through time-division multiplexing. The modulator can switch between different modulation modes and the demodulator can distinguish between different signal types based on their temporal patterns, making the system multi-functional without requiring separate dedicated circuits for each signal type.
3Manufacturing precision
If separate transmission channels are used for time-sensitive and non-time-dependent signals, then signal distortion is reduced, but productivity decreases
Solution Approach 1:
The system implements periodic time-division multiplexing where time-sensitive PWM signals are transmitted during dedicated first time periods with higher priority, and non-time-dependent bit-streams and status flags are transmitted during second time periods. This periodic separation maintains signal integrity while achieving efficient multiplexed transmission through a single channel.
Data Source
AI summary
A circuit is disclosed. The circuit includes a modulator circuit referenced to a first ground and arranged to receive at least a first status identifier signal and a second status identifier signal, a pulse width modulated (PWM) signal and a first bitstream signal, and in response generate a modulated signal; an isolation capacitor coupled between to the modulator circuit and a demodulator circuit, wherein the modulator circuit is arranged to transmit the modulated signal through the isolation capacitor to the demodulator circuit; and a clock generator circuit arranged to generate a clock signal (CK0), where the PWM signal and the first bitstream signal are synchronized with CK0; and where the demodulator circuit is referenced to a second ground and is arranged to receive the modulated signal and generate output signals corresponding to the first and second status identifier signals, the PWM signal and the first bitstream signal.