UBA2016AP datasheet(9/42 Pages) PHILIPS

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UBA2016A_15_15A

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Objective data sheet

Rev. 1 — 20 May 2011

9 of 42

NXP Semiconductors

UBA2016A/15/15A

600 V fluorescent lamp driver

7.3.1 VDD supply

The UBA2016A/15/15A is intended to be supplied by a start-up bleeder resistor

connected between the bus voltage VBUS and VDD and a dV/dt supply from the

half-bridge point at pin SHHB.

The IC starts up when the voltage at pin VDD rises above start-up voltage Vstartup(VDD) and

locks out (stops oscillating) when the voltage at pin VDD drops below stop voltage

Vstop(VDD). The hysteresis between the start and stop levels allows the IC to be supplied

by a buffer capacitor until the dV/dt supply is settled. The UBA2016A/15/15A has an

internal VDD clamp. This is an internal active Zener (or shunt regulator) that limits the

voltage on the VDD supply pin to clamp voltage Vclamp(VDD). No external Zener diode is

needed in the dV/dt supply circuit if the maximum current of the dV/dt supply minus the

current consumption of the IC (mainly determined by the gate drivers’ load) is below

Iclamp(VDD).

7.3.2 Low- and high-side drivers

The low- and high-side drivers are identical. The output of each driver is connected to the

equivalent gate of an external power MOSFET. The high-side driver is supplied by the

bootstrap capacitor, which is charged from the VDD supply voltage via an internal diode

when the low-side power MOSFET is on. The low-side driver is directly supplied by the

VDD supply voltage.

7.3.3 Non-overlap

During each transition between the two states GLHB HIGH/GHHB LOW and

GLHB LOW/GHHB HIGH, GLHB and GHHB will both be LOW for a fixed non-overlap time

tno to allow the half-bridge point to be charged or discharged by the load current

(assuming the load always has an inductive behavior), and enabling zero voltage

switching; see Figure 8.

UBA2016AP Datasheet(PDF) 9 Page - NXP Semiconductors