UDG-01065

UCC27423

GND

1

2

3

4

INB

INA

7

6

5

8

OUTA

VDD

OUTB

INPUT

1 µF

CER

100 µF

AL EL

DSCHOTTKY

VDD

C2

1 µF

VSNS

RSNS

0.1 Ω

C3

100 µF

10 Ω

+

VSUPPLY

5.5 V

ENBB

ENBA

UCC27423, UCC27424, UCC27425

www.ti.com

SLUS545D – NOVEMBER 2002 – REVISED MAY 2013

Two circuits are used to test the current capabilities of the UCC27423 driver. In each case external circuitry is

added to clamp the output near 5 V while the IC is sinking or sourcing current. An input pulse of 250 ns is

applied at a frequency of 1 kHz in the proper polarity for the respective test. In each test there is a transient

period where the current peaked up and then settled down to a steady-state value. The noted current

measurements are made at a time of 200 ns after the input pulse is applied, after the initial transient.

The first circuit in Figure 2 is used to verify the current sink capability when the output of the driver is clamped

around 5V, a typical value of gate-source voltage during the Miller plateau region. The UCC27423 is found to

The circuit shown in Figure 3 is used to test the current source capability with the output clamped to around 5 V

Figure 3.

It should be noted that the current sink capability is slightly stronger than the current source capability at lower

VDD. This is due to the differences in the structure of the bipolar-MOSFET power output section, where the

current source is a P-channel MOSFET and the current sink has an N-channel MOSFET.

In a large majority of applications it is advantageous that the turn-off capability of a driver is stronger than the

turn-on capability. This helps to ensure that the MOSFET is held OFF during common power supply transients

which may turn the device back ON.

Parallel Outputs

The A and B drivers may be combined into a single driver by connecting the INA/INB inputs together and the

OUTA/OUTB outputs together. Then, a single signal can control the paralleled combination as shown in Figure 4.

Copyright © 2002–2013, Texas Instruments Incorporated

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Product Folder Links: UCC27423 UCC27424 UCC27425