Agilent Technologies Z5623A manual Adjustable Voltage Regulator Circuit

Models: Z5623A

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Advanced Topics

Using the Control Lines Connector

The DUT may require a control voltage that is different from any of the existing power supply voltages. Rather than adding another power supply, a circuit such as the one shown in Figure 7-3can be used to derive the needed voltage from one of the existing power supply outputs. The IC shown in the figure is a 3-Terminal Adjustable Voltage Regulator (National Semiconductor Part No. LM317). It can supply a maximum output current of 1.5 A provided that (VIN - VOUT) ≤ 15 V.

The equations governing the circuit shown in Figure 4-13 are

3V ≤ (VIN - VOUT) ≤ 40 V 1.2 V ≤ VOUT

VC = (1.25 V)(1 + R2 / R1) + IADJ (R2)

IADJ = 50 ∝A (typical)

The equations show that the circuit can be adjusted for any output voltage (VC) from 1.2 V to 12.0 V provided that (a) a power supply voltage of 15 V is used and (b) the values of R1 and R2 shown in Figure 7-3are used.

Figure 7-3 Adjustable Voltage Regulator Circuit

National Semiconductor

LM317

Power

Supply

+

In Out

Adjust

1 F

R1 = 215

R2 = 2 k

+

VC

1F

VC can be adjusted from +1.2 to +12.0 V if Power Supply = +15 V

Agilent Technologies Z5623A Option H48

7 -9

Page 121
Image 121
Agilent Technologies Z5623A manual Adjustable Voltage Regulator Circuit