UBA2032T PHILIPS [NXP Semiconductors], UBA2032T Datasheet - Page 15

• Manufacturer Part Number: UBA2032T
• Description: Full bridge driver IC
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
Additional application information
G
At ignition of an HID lamp, a large EMC spark occurs. This
can result in a large voltage transient or oscillation at the
gates of the full bridge MOSFETs (LL, LR, HR and HL).
When these gates are directly coupled to the gate drivers
(pins GHR, GLR, GHL and GLL), voltage overstress of the
driver outputs may occur. Therefore it is advised to add a
resistor with a minimum value of 100
gate driver to isolate the gate driver outputs from the actual
power MOSFETs gate.
2002 Oct 07
ATE RESISTORS
Full bridge driver IC
in series with each
15
G
USE
The total gate current needed to charge the gates of the
power MOSFETs equals:
Where:
This current is supplied via the internal low voltage supply
(V
“Characteristics”, note 1), at higher frequencies and with
MOSFETs having a relative high gate charge, this
maximum V
anymore. As a result the internal low voltage supply (V
and the gate drive voltage will drop resulting in an increase
of the on resistance (R
this case an auxiliary low voltage supply is necessary.
I
gate
ATE CHARGE AND SUPPLY CURRENT AT HIGH FREQUENCY
I
f
Q
DD
gate
bridge
gate
). Since this current is limited to 11 mA (see table
=
= gate current
= gate charge.
4 f
= bridge frequency
DD
bridge
supply current may not be sufficient
Q
gate
on
) of the full bridge MOSFETs. In
.
Preliminary specification
UBA2032
DD
)