The electrical performance of the module power supply is presented through a series of tests. The following are general functional test items, as detailed below:
Line Regulation
Load Regulation
Conmine Regulation
Output ripple and noise (Ripple & Noise)
Input power inverter , Efficiency (Input Power, Efficiency)
Dynamic load or transient load (Dynamic or Transient Response)
Set-Up and Hold-Up time
General function (Functions) test
1, power adjustment rate
Power regulation is defined as the ability of a power supply to provide its regulated output voltage as the input voltage changes. The test procedure is as follows: After the heat supply is stabilized under normal input voltage and load conditions, the power supply is measured and recorded under low input voltage (Min), normal input voltage (Normal), and high input voltage (Max). Output voltage value. The power regulation rate is usually a percentage of the output voltage deviation caused by the input voltage change under a normal fixed load (Nominal Load), as shown in the following formula:
[Vo(max)-Vo(min)] / Vo(normal)
2, load adjustment rate
Load regulation is defined as the ability of a switching power supply to provide a stable output voltage when the output load current changes. The test procedure is as follows: after the heat supply of the power supply to be tested is stable under normal input voltage and load conditions, the output voltage value under normal load is measured, and then measured under light load (Min) and heavy load (Max) load respectively. Record the output voltage values ??(Vo(max) and Vo(min), respectively). The load regulation is usually the percentage of the output voltage deviation caused by the load current change at a normal fixed input voltage, as shown in the following formula. :
[Vo(max)-Vo(min)] / Vo(normal)
- Comprehensive adjustment rate
The integrated regulation is defined as the ability of the power inverter supply to provide a stable output voltage when the input voltage and output load current change. This is a combination of power regulation and load regulation. This test is a combination of the above power regulation and load regulation, which provides a more accurate performance verification of the power supply under varying input voltage and load conditions. The comprehensive adjustment rate is expressed in the following way: under the input voltage and output load current change, the deviation of the output voltage shall be within the specified upper and lower voltage range (ie, within the absolute value of the upper and lower limits of the output voltage) or within a certain percentage limit. .
4, output noise
Output noise (PARD) is the voltage value of the periodicity and random deviation of the average DC output voltage when the input voltage and the output load current are constant. The output noise is all the unwanted AC and noise components on the regulated and filtered DC output voltage (including the low frequency 50/60Hz power frequency multiplier signal, the high frequency switching signal above 20 KHz and its harmonics). Waves, which are combined with other random signals)), are usually expressed in units of peak voltages in mVp-p peaks.
The specifications of general switching power supplies are within the specification of output noise of less than 1% of the output DC output voltage, and the bandwidth is 20Hz to 20MHz. The worst case of the actual operation of the power supply (such as the maximum output load current, the lowest input power inverter supply voltage, etc.), if the power supply is in a harsh environment, its output DC voltage plus the instantaneous output voltage after the noise can still maintain stability. The output voltage does not exceed the output high and low voltage limit. Otherwise, the power supply voltage may exceed or fall below the logic voltage of the logic circuit (such as TTL circuit) and cause malfunction.
At the same time, the measuring circuit must have good isolation processing and impedance matching. In order to avoid unnecessary interference, ringing and standing waves on the wires, the double coaxial cable is generally used with 50Ω at its end point, and the differential amount is used. The measurement method (which avoids the noise current of the ground loop) is used to obtain the correct measurement result.
5, input power and efficiency
The input power inverter of the power supply is defined as the following formula:
True Power = Pav(watt) = Vrms x Arms x Power Factor is the integral value of the product of the input voltage and current in one week. Note that Watt≠VrmsArms is Watt=VrmsArmsxP.F., where PF is power. Power Factor, usually no power factor correction circuit power supply power factor is about 0.6 ~ 0.7, the power factor is between 1 ~ 0.
The efficiency of a power supply is defined as the ratio of the sum of the output DC power to the input power. Efficiency provides verification of the correct operation of the power supply. If the efficiency exceeds the specified range, it means that there is a problem in the design or the material of the part. If the efficiency is too low, the heat dissipation will increase and the service life will be affected.
6, dynamic load or transient load
A constant voltage output power supply is designed with a feedback control loop that continuously maintains a stable output voltage from its output voltage. Since the feedback control loop actually has a certain bandwidth, it limits the response of the power supply to changes in load current. If the phase of the control loop input and output is 1 when the gain (Unity Gain) is 1, more than 180 degrees, the output of the power supply will be unstable, out of control or oscillating. In fact, the load current when the power supply is working is also dynamically changing, rather than always maintaining the same (such as hard disk, floppy drive, CPU or RAM actions, etc.), so dynamic load testing is extremely important for the power inverter supply. The programmable electronic load can be used to simulate the worst load conditions in the actual operation of the power supply, such as the rapid rise of the load current, the slope of the drop, the period, etc. If the power supply is under severe load conditions, it can maintain a stable output voltage. Does not produce overshoot or undershoot.
POWER INVERTER 