Agilent Technologies E3630A service manual Load Regulation Load Effect

Current Limit

k.Disconnect all loads from the supply.

l.Connect the test setup shown in Figure A-5 to the +20- volt output. Substitute a short for RL and leave the load circuit switch open.

m.Set the voltage of the ±20V supplies to 20 volts.

n.Close the load switch and determine the current flow through the current sampling resistor (meter shunt) by measuring its voltage drop with the DVM. The current should be 0.55A±5% (0.5225A to 0.5775A).

o.Check the current limit of the -20V supply in the same way. Its short-circuit current should also be 0.55A±5% (0.5225A to 0.5775A).

p.Connect the test setup shown in Figure A-5 to the +6V

output. Close the switch, set the total resistance of RL and the current sampling resistor to an initial value of 2.4 Ω or greater, and set the output voltage to 6 volts.

q.Reduce the value of RL gradually while observing the out- put current indicated by the DVM. The current should increase to a maximum of 2.75A±5% (2.6125A to 2.8875A) before it begins to decrease.

r.Connect a short across RL and then recheck the current indicated by the DVM. The short-circuit current of this out- put should be 1A±15% (0.85A to 1.15A). Disconnect the test setup from the supply.

Load Regulation (Load Effect)

Definition: The change, ￿EOUT, in the static value of dc out- put voltage resulting from a change in load resistance from open circuit to the value that yields maximum rated output current (or vice versa).

To check the load regulation:

a.Connect the test equipment across the output of the +20V supply as shown in Figure A-6. Operate the elec- tronic load in constant current mode and set its current to the full rated value of the +20V supply.

b.Turn on the supply and adjust its voltage to its maximum rated value.

c.Record the voltage indicated on the DVM.

d.Operate the electronic load in open (input off) mode and recheck the DVM indication after reading settles. It should be within 0.01% plus 2mV of the reading in step (c).

e.Repeat steps (a) through (d) for each of the remaining supply outputs.

Line Regulation (Source Effect)

Definition: The change, ￿EOUT, in the static value of dc output voltage resulting from a change in ac input voltage from a minimum to a maximum value (±10% of nominal voltage).

To check the line regulation:

a.Connect a variable autotransformer between the input power source and the power supply line plug.

b.Connect the test equipment across the output of the +20V supply as shown in Figure A-6. Operate the elec- tronic load in constant current mode and set its current to the full rated value of the +20V supply.

c.Adjust the autotransformer for a low line input (-10% of nominal voltage).

d.Turn on the power, adjust the output of the supply to its maximum rated voltage, and record the DVM indication.

e.Adjust the autotransformer for high line voltage input (+10% of nominal voltage) and recheck the DVM indica- tion. It should be within 0.01% plus 2mV of the reading in step (d).

f.Repeat steps (b) through (e) for each of the remaining supply outputs.

Ripple and Noise

Definition: Ripple and noise are measured in the rms or peak- to-peak value over a 20 Hz to 20 MHz bandwidth. Fluctuations below the lower frequency limit are treated as drift.

RMS Measurement

The rms measurement is not an ideal representation of the noise, since fairly high output noise spikes of short duration could be present in the ripple and not appreciably increase the rms value.

To measure the ripple and noise of the rms value on each output supply output:

a.Connect the test equipment across the output of the +20V supply as shown in Figure A-7.

b.Turn on the supply and push +20V METER switch.

c.Turn up output voltage to the full rated value.

d.Check that the rms noise voltage at the true rms voltme- ter is less than 0.35mV.

e.Repeat for the remaining supply outputs.

Figure A-6. Basic Test Setup	Figure A-7. Ripple and Noise rms Measurement Test
	Setup

A-5