FAN3229 Fairchild Semiconductor, FAN3229 Datasheet - Page 18

• Manufacturer Part Number: FAN3229
• Description: (FAN3226 - FAN3229) Low-Side Gate Drivers
• Manufacturer: Fairchild Semiconductor

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© 2007 Fairchild Semiconductor Corporation
FAN3226 / FAN3227 / FAN3228 / FAN3229 • Rev. 1.0.3
Truth Table of Logic Operation
The FAN3228/FAN3229 truth table indicates the
operational states using the dual-input configuration. In
a non-inverting driver configuration, the IN- pin should
be a logic low signal. If the IN- pin is connected to logic
high, a disable function is realized, and the driver output
remains low regardless of the state of the IN+ pin.
In the non-inverting driver configuration in Figure 49,
the IN- pin is tied to ground and the input signal (PWM)
is applied to IN+ pin. The IN- pin can be connected to
logic high to disable the driver and the output remains
low, regardless of the state of the IN+ pin.
In the inverting driver application in Figure 50, the IN+
pin is tied high. Pulling the IN+ pin to GND forces the
output low, regardless of the state of the IN- pin.
IN+
Figure 49. Dual-Input Driver Enabled,
Figure 50. Dual-Input Driver Enabled,
0
0
1
1
Non-Inverting Configuration
Inverting Configuration
IN-
0
1
0
1
OUT
0
0
1
0
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Operational Waveforms
At power-up, the driver output remains low until the V
voltage reaches the turn-on threshold. The magnitude
of the OUT pulses rises with V
is reached. The non-inverting operation illustrated in
Figure 51 shows that the output remains low until the
UVLO threshold is reached, the output is in-phase with
the input.
For the inverting configuration of Figure 50, start-up
waveforms are shown in Figure 52. With IN+ tied to V
and the input signal applied to IN–, the OUT pulses are
inverted with respect to the input. At power-up, the
inverted output remains low until the V
reaches the turn-on threshold, then it follows the input
with inverted phase.
(VDD)
IN+
VDD
IN-
OUT
Figure 51. Non-Inverting Start-Up Waveforms
Figure 52. Inverting Start-Up Waveforms
DD
until steady-state V
Turn-on threshold
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DD
voltage
DD
DD
DD