33883 Datasheet, PDF (12/21 Pages) Freescale Semiconductor, Inc – H-Bridge Gate Driver IC

FUNCTIONAL DEVICE OPERATION
FUNCTIONAL DEVICE OPERATION
DRIVER CHARACTERISTICS
Figure 5 represents the external circuit of the high-side
gate driver. In the schematic, HSS represents the switch that
is used to charge the external high-side MOSFET through the
GATE_HS terminal. LSS represents the switch that is used to
discharge the external high-side MOSFET through the
GATE_HS terminal. A 180KΩ internal typical passive
discharge resistance and a 18 V typical protection zener are
in parallel with LSS. The same schematic can be applied to
the external low-side MOSFET driver simply by replacing
terminal CP_OUT with terminal LR_OUT, terminal GATE_HS
with terminal GATE_LS, and terminal SRC_HS with GND.
HSSDC_IN
IN_HS1
HSSpulse_IN
LSS_IN
CP_OUT
HSS
I_{charge HSS}
I_{discharge LSS}
I_{GATE_HS}
GATE_HS1
180
LSS
kΩ
18 V
SRC_HS1
Figure 5. High-Side Gate Driver Functional Schematic
The different voltages and current of the high-side gate
driver are illustrated in Figure 6. The output driver sources a
peak current of up to 1.0 A for 200 ns to turn on the gate. After
200 ns, 100 mA is continuously provided to maintain the gate
charged. The output driver sinks a high current to turn off the
gate. This current can be up to 1.0 A peak for a 100 nF load.
IN_HS1
0
HSSpulse_IN
0
HSS DC_IN
0
LSS_IN
I_{charge HSS}
0
I_{discharge LSS}
1.0 A Peak
100 mA Typical
1.0 A Peak
0
I_{GATE_HS}
0
1.0 A Peak
100 mA Typical
-1.0 A Peak
Note GATE_HS is loaded with a 100 nF capacitor in the
chronograms. A smaller load will give lower peak and DC charge or
discharge currents.
Figure 6. High-Side Gate Driver Chronograms
33883
12
Analog Integrated Circuit Device Data
Freescale Semiconductor