11/17

L6598

3.4 OP AMP Section

The integrated OP AMP is designed to offer Low Output Impedance, wide band, High input Impedance and wide

Common Mode Range. It can be readily used to implement protection features or a closed loop control. For this

3.5 Comparators

Two CMOS comparators are available to perform protection schemes. Short pulses (>= 200ns) on Comparators

Input are recognised. The EN1 input (active High), has a threshold of 0.6V (typical value) forces the device in a

latched shut down state (e.g. LVG Low, HVG low, Oscillator stopped), as in the Under Voltage Conditions. Nor-

mal Operating conditions are resumed after a power-off power-on sequence. The EN2 input (active high), with

a threshold of 1.2V (typical value) restarts a Soft Start sequence (see Timing Diagrams). In addition the EN2

Comparator, when activated, removes a latched shutdown caused by EN1.

Figure 15. Switching Time Waveform Definitions

Figure 16. Dead Time and Duty Cycle Waveform Definition

90%

90%

10%

10%

tf

tr

LVG

90%

90%

10%

10%

tf

tr

HVG

D98IN898

LVG

HVG

t d

50%

50%

t d

50%

50%

T1

50%

Tperiod

Dc =

Tperiod

T1

D98IN899