Technical Ashining—power system design chapter
pubdate：2018/06/27 13:25:00 posted by： visit times：541
Power supply is a deep subject. Excellent power supply design is an important guarantee that the whole system works stably. Besides the input voltage,output voltage,Max output current, the transient response is a important standard to measure the power supply.
What is transient response? Generally speaking,it is adjustment response capability of Output voltage, when input voltage change instantaneously(Instantly pull high and pull down)
The output voltage of the power system with poor transient response is affected by the input voltage, which may fluctuate greatly and may cause the power receiving circuit to burn due to overvoltage or unstable operation due to undervoltage.
The following is a typical power supply design case with poor transient response. Channel one (yellow) is the input voltage and channel two (cyan) is the output voltage.
[figure 1 - a 32 module power subsystem]
[Fig. two - the input output voltage curve of the power supply subsystem of a 32 module.]
When a 32 module is powered on, the power supply output voltage overshoots to 5.04V, then drops to 2.56V, and finally stabilizes to 3.36V. The overshoot voltage is as high as about 50%. It can be seen that the phase margin of the power subsystem design is insufficient. When the input voltage step changes, the output voltage response is not timely, resulting in large oscillation and poor design. Its 5.04V voltage can greatly exceed the maximum input voltage that the rear stage circuit can withstand, which greatly increases the risk of overvoltage damage in the latter stage.
Excellent power supply design should be considered comprehensively, rather than just considering individual parameters. Taking AS32-TTL-1W as an example, Ashining carried out rigorous experimental screening for its supporting power subsystem during its research and development process, and provided users with stable and reliable products.
Note: AS32-TTL-1W is a cost-effective LoRa wireless module developed by Ashining Technology based on the SX1278 RF solution.
[Fig. three - AS32-TTL-1W power subsystem]
[picture 4 - AS32-TTL-1W at Power-on moment, Power Subsystem Input and Output Voltage Curve]
When the AS32-TTL-1W power subsystem is powered on, the output transient response is excellent, there is no overshoot, and the output voltage stable settling time is less than 400uS. It can be seen that the power subsystem meets the transient power supply requirements of the RF circuit.
Ashining Technology always adheres to the design concept of combining theory with experimental verification, and provides users with stable and reliable wireless communication products with seriousness and dedication.