High-Resolution Current Source Using Digital PWM Control
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Solution Overview
Problem
Current current sources lack the ability to deliver currents with a high degree of resolution, which is essential for precise control in various electrical circuits.
Innovation Solution
A circuit and method that utilize a digital circuit to generate a pulse width modulation signal with a controllable duty cycle based on configuration data, which is then used to calculate a weighted average of multiple voltages to control a voltage-controlled current source, allowing for precise and high-resolution output current control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current sources are used, then the circuit operation is simple, but the current control resolution is low
Solution Approach 1:
The current control is segmented into multiple discrete levels using a digital circuit with multiple output states. The digital circuit divides the current range into distinct segments that can be independently controlled, enabling high-resolution current control through digital bit combinations rather than continuous analog adjustment.
Solution Approach 2:
A digital circuit acts as an intermediary between the control signal and the current source. This digital intermediary processes control data and generates corresponding current levels, providing precise control resolution while maintaining circuit simplicity through standardized digital logic components.
2Manufacturing precision
If high-resolution current control is implemented, then the current precision is improved, but the circuit complexity increases
Solution Approach 1:
The patent replaces complex analog mechanical adjustment mechanisms with a digital circuit system. Instead of using continuous analog controls that require precise physical adjustments, the system uses digital logic circuits that can be programmed and controlled electronically, achieving high precision through digital bit manipulation rather than mechanical fine-tuning.
Solution Approach 2:
The circuit changes its operating parameters dynamically based on digital control inputs. By varying the digital control state (bit combinations), the circuit adjusts the current output to different precise levels. This parameter change approach allows high-resolution control without requiring complex physical circuit reconfiguration.
3Measurement precision
If a digital circuit with PWM signal is used, then the current control resolution is improved, but the device complexity increases
Solution Approach 1:
The digital circuit generates periodic PWM (pulse-width modulation) signals to control the current output. By varying the duty cycle of these periodic pulses, the system achieves high-resolution current control. The periodic nature of the PWM signal allows for efficient switching operation and precise average current control through digital duty cycle adjustment.
Solution Approach 2:
The PWM generator acts as an intermediary that converts digital control words into analog-equivalent current control. This intermediary component simplifies the overall device architecture by providing a standardized interface between digital logic and analog current output, avoiding the need for complex direct digital-to-current conversion circuits.
Data Source
AI summary
A circuit for generating an output current and a method for generating an output current are provided. A voltage generator circuit is configured to generate at least two voltages. A digital circuit is configured to generate a pulse width modulation signal having a waveform characteristic that is controllable based on bits of configuration data received by the digital circuit. An averaging circuit is configured to receive the pulse width modulation signal and generate a bias voltage that comprises a weighted average of the at least two voltages. Weights of the at least two voltages are based on the waveform characteristic of the pulse width modulation signal. A voltage-controlled current source is configured to generate an output current based on the bias voltage.