Complementary Output Generator with Programmable Deadband Control
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Solution Overview
Problem
Conventional complementary output generator (COG) modules lack enhanced functionality and operational flexibility in microcontroller applications, particularly in power management and signal generation tasks, such as switched-mode power supplies and motor speed control.
Innovation Solution
A configurable COG module with programmable rising and falling event inputs, clock multiplexing, blanking and deadband control, output polarity reversal, and steering capabilities, allowing for various operating modes like half-bridge, push-pull, and full-bridge configurations, along with independent event enable delays and phase control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional COG modules are used, then basic signal generation is achieved, but operational flexibility and functionality are limited
Solution Approach 1:
The COG module is designed to perform multiple functions including half-bridge, push-pull, and full-bridge configurations through programmable event inputs and output steering capabilities. The module can generate complementary outputs from various triggering sources (PWM, comparators, frequency generators) and supports multiple operating modes, making it a universal signal generation device that replaces several dedicated circuits.
Solution Approach 2:
The module employs programmable blanking times and deadband periods that can be dynamically adjusted through software configuration. The rising and falling event inputs can be independently programmed with different blanking times, and the deadband period between complementary outputs can be dynamically controlled to prevent shoot-through currents. This dynamic configurability enhances adaptability without requiring hardware changes.
2Reliability
If output signals are generated without deadband control, then signal generation speed is improved, but shoot-through currents occur
Solution Approach 1:
The module implements a programmable deadband period that is automatically inserted between the falling edge of one complementary output and the rising edge of the other. This preliminary timing control prevents shoot-through currents by ensuring both outputs are in a high-impedance state during the deadband interval, eliminating the risk of simultaneous conduction before the next output transition.
Solution Approach 2:
The deadband control mechanism acts as an intermediary timing element between the complementary output signals. It mediates the transition between opposite polarity outputs by introducing a controlled delay period, during which both outputs are held in a safe state, thus preventing harmful current paths while maintaining reliable signal generation.
3Reliability
If event inputs are immediately processed, then response time is reduced, but false triggering from noise occurs
Solution Approach 1:
The module implements programmable blanking times that are automatically applied to rising and falling event inputs before they are processed. This preliminary filtering action blocks transient noise spikes and false triggering conditions during the blanking interval, ensuring that only valid, sustained events trigger output transitions. The blanking time can be programmatically adjusted to match the expected signal characteristics.
Solution Approach 2:
The blanking circuit performs preliminary anti-action by preemptively blocking potentially harmful noise inputs before they can cause false triggering. By introducing a temporary inhibition period after each detected event, the system prevents subsequent noise spikes from being misinterpreted as valid trigger signals, thus maintaining signal accuracy while minimizing response delay through programmable timing.
Data Source
AI summary
A complementary output generator (COG) module generates at least two complementary outputs determined by rising and falling event sources. In a simple configuration of the COG module, the rising and falling event sources are the same signal which is a signal having the desired period and duty cycle. The COG module converts this single signal input into dual complementary outputs. The frequency and duty cycle of the dual outputs substantially match those of the single input signal. Blanking and deadband times may be introduced between the complementary outputs, and the dual complementary outputs may also be phase delayed. In addition the COG module may provide up to four outputs for controlling half and full-wave bridge power applications.