RE46C317/18 Piezoelectric Horn Driver

RE46C317/18: Piezoelectric Horn Driver with Boost Converter

The RE46C317 is a Complimentary Metal-Oxide Semiconductor (CMOS) piezoelectric horn driver IC with built-in boost converter. It is intended for use in 3 V battery or battery-backed applications. The circuit features a dc-to-dc boost converter and a driver circuit suitable for driving a piezoelectric horn. The RE46C317 is compatible with the RE46C117 and offers lower standby current. The RE46C317 provides a tri-state input for horn enable.

RE46C317/18 Features

  • 3V operation
  • Low quiescent current
  • 10 V on-board boost converter
  • Low horn driver on resistance

RE46C317/18 Applications

  • Smoke detectors
  • CO detectors
  • Personal security products
  • Electronic toys

RE46C317/18 Typical Application

  • Schottky diode D1 must have the maximum peak current rating of at least 1 A. For best results, the forward voltage spec should be less than 0.5 V at 1 A.
  • Inductor L3 must have the maximum peak current rating of at least 1A. For best results, the DC resistance should be less than 0.5 Ω.

RE46C317/18 Pin Function Table

Pin Number Symbol Description
1 FEED Horn feedback
2 VDD Positive supply voltage
3 LX External inductor
4 VSS Negative supply voltage
5 VO Output of boost converter
6 HORNB Horn Brass
7 HORNS Horn Silver
8 HRNEN Horn Enable

RE46C317/18 Pin Descriptions

Horn Feedback Pin (FEED)

This pin is usually connected to the feedback electrode of the piezoelectric horn through a current limiting resistor. If not used, this pin must be connected to VSS.

Positive Supply Pin (VDD)

This pin is connected to the positive supply voltage of the system.

External Inductor Pin (LX)

This is the open drain NMOS output used to drive the boost converter inductor. The inductor should be connected from this pin to the positive supply voltage through a low resistance path.

Negative Supply Pin (VSS)

This pin is connected to the negative supply voltage of the system.

Boost Converter Output Pin (VO)

This is the output pin of the boost converter, typically 10 V.

Horn Brass Pin (HORNB)

This pin is connected to the metal electrode (B) of the piezoelectric transducer.

Horn Silver Pin (HORNS)

This is the complementary output to HORNB. It connects to the ceramic electrode (S) of the piezoelectric transducer.

Horn Enable Pin (HRNEN)

This is the logic input for horn enable. The pin function table shows the different HRNEN states and their description.

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