AN3399 datasheet(14/24 Pages) STMICROELECTRONICS

14 / 24 page

Evaluations of circuit with PNP and current limitation

AN3399

14/24

Doc ID 018824 Rev 2

Figure 11.

V3 switch ON /OFF to shortcut

2.2.2

Load switch ON/OFF

Measurements were done for circuit from Figure 4. As load an electronically controlled load

was used with following preset parameters:

●

R1, R2, R3, R4, R5 = 10 K

●

Device type = Chroma 63103

●

Mode = constant current low

●

Current = 200 mA

●

Slope = 250 mA/µs (falling and rising)

Figure 12.

Load switching

2.2.3

Influence of Ci and C1 on the V3 switch and load variation response

For the circuit from Figure 4 the influence of capacitors Ci and C1 to the regulator switching

ON/OFF response for V3 output open load and 25  load (200 mA @ 5 V) were tested.

The influence to the load regulation by switching ON / OFF load of 200 mA (electronic

controlled load was used for these tests) were also tested.

The capacitors influence was tested on following combinations Ci and C1:

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