Diamond View DV154, Service Manual

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DV154/154B LCD Monitor Service Guide
Circuit operation theory
10
Fig. 8
The Tl1451AC incorporates on a single monolithic chip all the functions required in the construction of two
pulse-width modulation control circuits. Designed primarily for power supply control, the TL1451AC contains an
on-chip 2.5V regulator two error amplifiers, an adjustable oscillator, two dead-time comparators, undervoltage
lockout circuitry, and dual common-emitter output transistor circuits. The uncommitted output transistors provide
common-emitter output capability for each controller. The internal amplifiers exhibit a common-mode voltage
range from 1.04V to 1.45V. The dead-time control comparator has no offset unless externally altered and can
provide 0% to 100% dead time. The on-chip oscillator can be operated by modulating RT and CT. During low
Vcc conditions, the undervoltage lockout control circuit feature locks the outputs off until the internal circuitry is
operational.