Switching Power Supply Dead-Time Control for Accurate Envelope Tracking
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Solution Overview
Problem
Existing switching power supply circuits face challenges in accurately following the voltage of envelope signals or subcarrier signals, leading to inefficiencies in power supply and amplification devices.
Innovation Solution
A switching power supply circuit with an upper arm and lower arm coupled in series, a drive circuit that alternately turns on these arms across a dead time, and an adjustment circuit that dynamically adjusts the dead time based on the input signal voltage to ensure the output voltage closely follows the envelope or subcarrier signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the dead time is fixed in the drive circuit, then the circuit structure is simple, but the output voltage cannot accurately follow the input signal voltage
Solution Approach 1:
The dead time is changed from a fixed value to a dynamically adjustable parameter. The adjustment circuit modifies the dead time based on the input signal voltage, allowing the output voltage to accurately follow the input signal while maintaining circuit simplicity through automated control.
Solution Approach 2:
The dead time parameter is varied according to the input signal voltage. When the input signal voltage is high, the dead time is shortened; when the input signal voltage is low, the dead time is lengthened. This parameter adjustment enables accurate voltage tracking without complex circuit redesign.
2Measurement precision
If the dead time is shortened to improve voltage tracking, then the output voltage follows the input signal better, but the risk of shoot-through current increases
Solution Approach 1:
The dead time is dynamically adjusted based on the input signal voltage level. At high voltage levels where tracking accuracy is critical, the dead time is shortened. At low voltage levels where shoot-through risk is higher, the dead time is lengthened, thus balancing tracking accuracy with safety.
Solution Approach 2:
Different dead time values are applied under different operating conditions. The circuit uses localized optimization by setting appropriate dead time for each voltage level, rather than using a single conservative value for all conditions, thereby improving overall system performance and safety.
3Reliability
If the dead time is lengthened to prevent shoot-through current, then the reliability improves, but the output voltage tracking accuracy deteriorates
Solution Approach 1:
The dead time parameter is adaptively changed based on the input signal voltage. The adjustment circuit ensures that the dead time is sufficient to prevent shoot-through current while being short enough to maintain good voltage tracking accuracy, optimizing both reliability and performance simultaneously.
Data Source
AI summary
A switching power supply includes a switching power supply circuit that has an upper arm and a lower arm that are coupled in series. The switching power supply further includes a drive circuit that alternately turns on the upper arm and the lower arm across a dead time in which the upper arm and the lower arm are turned off such that an output voltage of the switching power supply circuit follows a voltage of an input signal that is an envelope signal or a subcarrier signal; and an adjustment circuit that adjusts the dead time according to the voltage of the input signal.