ML4836

5

FUNCTIONAL DESCRIPTION

The ML4836 consists of flexible ballast control section.

Start-up and lamp-out retry timing are controlled by the

selection of external timing components, allowing for

control of a wide variety of different lamp types. The

ballast section controls the lamp power using frequency

modulation (FM) with additional programmability

provided to adjust the VCO frequency range. This allows

for the IC to be used with a variety of different output

networks. Figure 1 depicts a detailed block diagram of

ML4836.

The ML4836 provides several safety features. See the

corresponding sections for more details:

• End-of-lamp life detection to detect EOL and shut-off

lamps; See End Of Life Section.

• Thermal shutdown for temperature sensing extremes;

See IC Bias, Under-Voltage Lockout and Thermal

Shutdown Section.

• Relamping starting with anti-flash for programmable

restart for lamp out conditions while minimizing

“flashing” when powering from full power to dimming

levels; See Starting, Re-Start, Preheat and Interrupt

Section

Figure 1. Detailed Block Diagram

VCC

14

REF

1

AGND

10

RSET

4

LAMP FB

2

LEAO

3

RT2

5

INTERRUPT

7

PWDET

9

PGND

11

OUT B

12

OUT A

13

REF

–

+

14V

+

–

6.75V

Q

Q

T

1.20V/1V

RX/CX

6.65V/1.25V

2.5V

+

–

1.05V

Q

Q

S

R

CLK

UVLO

REF_OK

PREHEAT

THERMAL SHUTDOWN

RT/CT

6

OSCILLATOR

+

–

4.65V/

1.75V

S

Q

Q

R

+

–

COMP

–

+

–

+

+

–

TEMP

140ºC/100ºC

RX/CX

8