Integrated OOK Oscillator Circuit for Low-Power Signal Isolators
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Solution Overview
Problem
Existing OOK-based signal isolators have inefficient designs and are power-hungry due to the need for separate high-frequency oscillators, which increases device size and power consumption.
Innovation Solution
The proposed solution integrates an oscillator circuit with a control switch and a quenching switch within the isolator device, using parasitic capacitance and inductive properties to generate oscillating signals, and includes a kickstart circuit to reduce latency and improve throughput by facilitating faster transitions between ON and OFF states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate high-frequency oscillator is used to generate carrier signals, then the isolator can transmit signals across galvanic isolation barriers, but the device size and power consumption increase
Solution Approach 1:
The patent combines the oscillator circuit with the isolator device itself, integrating functions that were previously separate. The isolator now contains an integrated oscillator that generates carrier signals internally, eliminating the need for external oscillator components and reducing overall device footprint while maintaining signal transmission capability across galvanic isolation barriers
2Reliability
If a separate high-frequency oscillator is used to generate carrier signals, then the isolator can transmit signals across galvanic isolation barriers, but the device size increases
Solution Approach 1:
The oscillator circuit is merged with the isolator device structure, creating a compact integrated design where the carrier signal generation function is built into the isolation barrier architecture itself, reducing the total device area required
Solution Approach 2:
The isolator device performs multiple functions: it provides galvanic isolation, generates carrier signals, and transmits modulated data. This multi-functional integration eliminates the need for separate dedicated oscillator components, thereby reducing device size
3Reliability
If traditional OOK-based isolator design is used, then signal transmission across isolation barriers is achieved, but transmission efficiency is reduced due to latency
Solution Approach 1:
The kickstart circuit pre-charges the oscillator tank circuit before formal oscillation begins, and the quenching circuit rapidly stops oscillation when transitions are required. These preliminary and follow-up actions reduce the time needed for the oscillator to reach full amplitude and to stop oscillating, thereby reducing overall transmission latency
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 design reduces the component count and area requirements, decreases latency, and enhances the efficiency of signal transmission across isolation barriers, leading to improved power management and faster operation.
Implementation Method 1
using parasitic capacitance and inductive properties to generate oscillating signals
Implementation Method 2
using parasitic capacitance and inductive properties to generate oscillating signals
Data Source
Figure 1~2(b)
Figure 3(a)~3(b)
Figure 4(a)~4(b)
AI summary
An oscillator for a signal isolator system includes a capacitor and an inductor connected in parallel, two pairs of cross-coupled switches and a control switch. The capacitor, the inductor and the cross-coupled switches form an oscillator. The control switch controls operation of the oscillator between an ON state and an OFF state in response to a data signal to be communicated across an isolation barrier. The inductor may be formed from a winding of an isolation transformer, which reduces component count as compared to a system that provides a separate inductor. Other embodiments may include a current-supplying kickstart circuit and a shorting transistor that can speed transition between the ON and OFF states.