HV861

DS20005911B-page 6

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2023-2026 Microchip Technology Inc. and its subsidiaries

2.0

PIN DESCRIPTION

The details on the pins of HV861 are listed in Table 2-1.

Refer to

Package Type for the location of pins.

TABLE 2-1:

PIN FUNCTION TABLE

Pin Number

Pin Name

Description

1

REL-Osc

External resistor from REL-Osc to VDD sets the EL frequency. The EL frequency is

inversely proportional to the external REL resistor value. Reducing the resistor

value by a factor of two results in an increase in the EL frequency by two.

2

RSW-Osc

External resistor from RSW-Osc to VDD sets the switch converter frequency. The

switch converter frequency is inversely proportional to the external RSW resistor

value. Reducing the resistor value by a factor of two results in an increase in the

switch converter frequency by two.

3

VDD

Low-voltage input supply pin

4

EN1

Enable input signal for EL Lamp 1. CMOS logic input pin. (Refer to Table 3-2.)

5

EN2

Enable input signal for EL Lamp 2. CMOS logic input pin. (Refer to Table 3-2.)

6

GND

Device ground

7

LX

Drain of internal switching MOSFET. Connection for an external inductor. The

inductor LX is used to boost the low-input voltage by inductive flyback. When the

internal switch is on, the inductor is being charged. When the internal switch is off,

the charge stored in the inductor is transferred to the high-voltage capacitor, CS.

The energy stored in the capacitor is connected to the internal H-bridge, and there-

fore to the EL lamp. In general, smaller value inductors, which can handle more

current, are more suitable to drive larger size lamps. As the inductor value

decreases, the switching frequency of the inductor (controlled by RSW) should be

increased to avoid saturation.

8

CS

Connect a 100V capacitor between this pin and ground. This capacitor stores the

energy transferred from the inductor.

9

EL2

EL Lamp 2 connection

10

COM2

Common connection for EL2 Lamp

11

COM1

Common connection for EL1 Lamp

12

EL1

EL Lamp 1 connection

13

PWM

PWM pulse input for EL lamp dimming. The duty cycle of the PWM signal is

inversely proportional to the output voltage. If PWM dimming is not desired, then

the PWM pin should be tied to ground.

14

VOUT

Switched internal reference voltage

15

VREG

Input voltage to set VCS regulation voltage. This pin allows an external voltage

source to control the VCS amplitude. EL lamp dimming can be accomplished by

varying the input voltage to VREG. The VCS voltage is approximately 71 times the

voltage seen on VREG. External resistor connected between VREG and VOUT pins

controls the VCS charging rate. The charging rate is inversely proportional to the

resistor value.

fEL 2M



190Hz



REL

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=

fSW 825k



100kHz



RSW

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=