04-02-2013, 09:49 AM
High voltage resonant controller
1High voltage.pdf (Size: 356.5 KB / Downloads: 25)
Features
High voltage rail up to 600 V
dV/dt immunity ±50 V/ns in full temperature
range
Driver current capability: 250 mA source
450 mA sink
Switching times 80/40 ns rise/fall with 1 nF load
CMOS shutdown input
Undervoltage lock-out
Soft-start frequency shifting timing
Sense op amp for closed loop control or
protection features
High accuracy current controlled oscillator
Integrated bootstrap diode
Clamping on Vs
SO16, DIP16 packages
Description
The device is manufactured with the BCD OFF
LINE technology, able to ensure voltage ratings
up to 600 V, making it perfectly suited for AC/DC
Adapters and wherever a resonant topology can
be beneficial. The device is intended to drive two
power MOSFET, in the classical half bridge
topology. A dedicated timing section allows the
designer to set soft start time, soft start and
minimum frequency. An error amplifier, together
with the two enable inputs, are made available. In
addition, the integrated bootstrap diode and the
zener clamping on low voltage supply, reduces to
a minimum the external parts needed in the
applications.
High/low side driving section
An high and low side driving section provide the proper driving to the external power MOS or
IGBT. An high sink/source driving current (450/250 mA typ) ensure fast switching times also
when size for power MOS are used. The internal logic ensures a minimum dead time to
avoid cross-conduction of the power devices.
Timing and oscillator section
The device is provided of a soft start function. It consists in a period of time, TSS, in which
the switching frequency shifts from fstart to fmin. This feature is explained in the following
description (ref. fig.7 and fig.8).
Bootstrap section
The supply of the high voltage section is obtained by means of a bootstrap circuitry. This
solution normally requires an high voltage fast recovery diode for charging the bootstrap
capacitor (fig. 14a). In the device a patented integrated structure, replaces this external
diode. It is released by means of a high voltage DMOS, driven synchronously with the low
side driver (LVG), with in series a diode, as shown in fig. 14b.
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 purpose the op amp output can be properly
connected to Rfmin pin to adjust the oscillation frequency.