33899 Datasheet, PDF (18/26 Pages) Freescale Semiconductor, Inc – Programmable H-Bridge Power IC

FUNCTIONAL INTERNAL BLOCK DESCRIPTION
INTRODUCTION
The PWM input is connected to the system
microprocessor and provides for control of the four MOSFET
outputs. The PWM duty cycle range is 0% to 100%; however,
open load detection circuits require a minimum off-time.
The 33899 holds all outputs off if both FWD and REV are
either logic [0]s or logic [1]s. Figure 12 depicts inputs versus
outputs in forward mode operation.
V_IGNP + V_F
S0
V_IGNP -
R_DS(ON) * I_LOAD
R_DS(ON) * I_LOAD
Load
Current
PWM
INPUT
M1 GATE
M2 GATE
Dead
Time
M3 is “ON”
M4 is “OFF”
Figure 12. 33899 Operation in Forward Mode
33899
18
Analog Integrated Circuit Device Data
Freescale Semiconductor