The function of module power supply
Adjustment of output voltage
For module power products with TRIM or ADJ (adjustable) output pins, they can be operated through the REM terminal. There are two general control methods: (1) REM connected to - VIN (reference ground), remote control off, VREF<0.4V required. REM suspended or connected to+VIN, module working, VREM>1V required. (2) REM is connected to VIN, remote control is turned off, VREM<0.4V is required. REM is connected to+VIN, the module operates, and VREM is required to be greater than 1V. REM hovering, remote control shutdown, also known as "hovering shutdown" (- R). If the control needs to be isolated from the input end, a optocoupler can be used to transmit the control signal.
Combination of modules
(1) Parallel expansion. Parallel connection of the output terminals of the same module can enhance the output capacity, but the output voltage of the parallel modules should be adjusted relatively uniformly to ensure relative current sharing and avoid unnecessary oscillations. For modules with high current output, the lead resistance can also be carefully designed to achieve current sharing effect. The number of modules connected in parallel using this method should not exceed 2. Meanwhile, if one of the module outputs malfunctions, the entire system will not function properly. The parallel expansion connection circuit RL is the load.
(2) Redundant hot backup in parallel. Parallel connection of the same module output terminals through diodes can enhance the output capability and improve the reliability of the power system. In principle, if combined with the corresponding output alarm circuit, the module should be placed on a detachable busbar, so that faulty modules can be replaced in a timely manner. The modules connected in parallel using this method have no quantity limit. D is generally a Schottky diode.
(3) Series expansion. Serializing the output terminals of the same module can double the output voltage and increase the power accordingly, and a diode must be connected to the series output terminal for protection.
Backup and use of Ringflow
Ring flow generator is mainly used in telephone exchange to provide ringing to telephone users, usually used in a biased state. Bias can be divided into positive bias and negative bias. In order to improve the reliability of the bell flow system, it is necessary to backup the bell flow.
