9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification, and TI

does not warrant its accuracy or completeness. TI’s customers are responsible for determining

suitability of components for their purposes. Customers should validate and test their design

implementation to confirm system functionality.

9.1 Application Information

In this application, two 2-input AND gates with open-drain outputs are combined to produce a 4-input AND gate

function as shown in Figure 9-1. The remaining two gates can be used for another application in the system, or

the inputs can be grounded and the channels left unused.

The SN74HCS09 is used to directly control the RESET pin of a motor controller. The controller requires four

input signals to all be HIGH before being enabled, and should be disabled in the event that any one signal goes

LOW. The 4-input AND gate function combines the four individual reset signals into a single active-low reset

signal.

9.2 Typical Application

OC

PG

CASE

ON/OFF

RESET

Power Supply

Motor Controller

On/Off Switch

Case Tamper

Switch

Over Current

Detection

Rpu

VCC

Figure 9-1. Typical application block diagram

9.2.1 Design Requirements

• All signals in the system operate at the same voltage within the recommended operating range of the device

• The motor controller should be disabled if any of these conditions apply:

– Power Supply is not ready (PG)

– Excessive current is detected ( OC)

– Excessive temperature is detected ( OT)

– The power switch is in the OFF position (ON/ OFF)

SN74HCS09

SCLS779A – JUNE 2020 – REVISED OCTOBER 2020

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