RE46C317/18: Piezoelectric Horn Driver with Boost Converter
The RE46C317 is a Complementary Metal-Oxide Semiconductor (CMOS) piezoelectric horn driver Integrated Circuit (IC) with a built-in boost converter. It is intended for use in 3 V battery or battery-backed applications. The circuit features a Direct Current (DC)-to-DC boost converter and a driver circuit suitable for driving a piezoelectric horn. The RE46C317 is compatible with the RE46C117 and offers a lower standby current. The RE46C317 provides a tri-state input for horn enable.
RE46C317/18 Features
- 3 V operation
- Low quiescent current
- 10 V on-board boost converter
- Low horn driver on resistance
RE46C317/18 Applications
- Smoke detectors
- Carbon Monoxide (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 1 A. 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.