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Application Information

Product Overview Description

The ACPL-P346/W346 is an optically isolated power

output stage capable of driving power or SiC. Based on

BCDMOS technology, this gate drive optocoupler deliv-

ers higher peak output current, better rail-to-rail output

voltage performance and two times faster speed than the

previous generation products.

The high peak output current and short propagation de-

lay are needed for fast MOSFET switching to reduce dead

time and improve system overall efficiency. Rail-to-rail

output voltage ensures that the MOSFET’s gate voltage is

driven to the optimum intended level with no power loss

across the MOSFET. This helps the designer lower the sys-

tem power which is suitable for bootstrap power supply

operation.

It has very high CMR(common mode rejection) rating

which allows the microcontroller and the MOSFET to op-

erate at very large common mode noise found in indus-

trial motor drives and other power switching applications.

The input is driven by direct LED current and has a hys-

teresis that prevents output oscillation if insufficient LED

driving current is applied. This will eliminates the need of

additional Schmitt trigger circuit at the input LED.

The stretched SO6 package which is up to 50% smaller

than conventional DIP package facilitates smaller and

more compact design. These stretched packages are com-

pliant to many industrial safety standards such as IEC/EN/

DIN EN 60747-5-5, UL 1577 and CSA.

Recommended Application Circuit

The recommended application circuit shown in Figure 22

illustrates a typical gate drive implementation using the

ACPL-P346.

The supply bypass capacitors (1 µF) provide the large tran-

sient currents necessary during a switching transition. Be-

cause of the transient nature of the charging currents, a

low current (4.0 mA) power supply will be enough to pow-

er the device. The split resistors (in the ratio of 1.5:1) across

the LED will provide a high CMR response by providing a

balanced resistance network across the LED.

and controls the MOSFET switching times.

In PC board design, care should be taken to avoid routing

the MOSFET drain or source traces close to the ACPL-P346

input as this can result in unwanted coupling of transient

signals into ACPL-P346 and degrade performance.

Figure 22. Recommended application circuit with split resistors LED.

+_

+_

Rg

Q1

Q2

+HVDC

-HVDC

1µF

1

2

3

6

5

4

CATHODE

NC

ANODE

232Ω

154Ω