Microchip Technology HV853
The HV853 is a high-voltage low-noise, inductorless EL lamp driver. It is the low-noise version of the HV852 with improved electromagnetic interference (EMI) performance, operating over an input voltage range of 3.2V to 5V. It is designed to drive EL lamps of up to 1.5 in2, with capacitive values of up to 5.3 nF.FEATURES
● No External Components required when using an External Electroluminescent (EL) Clock Frequency● EL Frequency can be set by an External Resistor
● Low Noise
● DC to AC Converter
● Drives up to 5.3 nF (approximately 1.5 in2 Lamp) Load
● Output Voltage Regulation
● Enable Function
● EL Lamp Dimming
APPLICATIONS
● Cellular Phone Keypad● Watches
● Small Handheld Wireless Devices
● MP3 Players
GENERAL DESCRIPTION
The HV853 converts a low-voltage DC input to a high-voltage AC output across an EL lamp. A nominal regulated output voltage of ±80V is applied to the EL lamp. It uses a charge pump scheme to boost the input voltage, eliminating the need for an external inductor, diode, and high-voltage capacitor commonly found in conventional topologies. The charge pump circuit discharges its energy into an EL lamp through a high-voltage H-bridge. Once the voltage reaches its regulated limit, it is turned off to conserve power. The EL lamp is then discharged to ground and the H-bridge changes state to allow the charge pump to charge the EL lamp in the opposite direction.