SI9978 Datasheet, PDF (1/6 Pages) Vishay Siliconix – Configurable H-Bridge Driver

Configurable H-Bridge Driver
Si9978
Vishay Siliconix
FEATURES
D H-Bridge or Dual Half-Bridge Operation
D 20- to 40-V Supply
D Static (dc) Operation
D Cross-Conduction Protected
D Current Limit
D Undervoltage Lockout
D ESD Protected
D Fault Output
DESCRIPTION
The Si9978 is an integrated driver for an n-channel MOSFET
H-bridge. The mode control allows operation as either a full
H-bridge driver or as two independent half-bridges. The
DIR/PWM input configuration allows easy implementation of
either sign/magnitude or anti-phase PWM drive schemes for
full H-bridges. Schmitt triggers on the inputs provide logic
signal compatibility and hysteresis for increased noise
immunity. An internal low-voltage regulator allows the device
to be powered directly from a system supply of 20 to 40 volts.
All n-channel gates are driven directly from low-impedance
outputs. The addition of one external capacitor per half-bridge
allows internal circuitry to level shift both the power supply and
logic signal for the high-side n-channel gate drives. Internal
charge pumps replace leakage current lost in the high-side
driver circuits to provide “static” (dc) operation in any output
condition. Protection features include an undervoltage
lockout, cross-conduction prevention logic, and overcurrent
monitors.
The Si9978 is available in both standard and lead (Pb)-free,
24-pin wide-body SOIC (surface mount) packages, specified
to operate over the industrial (−40 to +85_C) temperature
range.
FUNCTIONAL BLOCK DIAGRAM
V+ ²⁴
V_DD
1
DIR/IN_A
3
QS/IN_B
5
PWM/EN_B
4
MODE
6
BRK
7
EN/EN_A
2
CL/FAULT_B
8
9
FAULT/FAULT_A
R_A/C_A
11
R_B/C_B
12
Low-Voltage
Regulator
V_DD
Low-Side
U.V. Lockout
V_DD
V_DD
V_DD
V_DD
V_DD
V_DD
CAP_A
CAP_B
High-Side
U.V. Lockout
Input
Logic
One Shot
One Shot
Document Number: 70011
S-40804—Rev. E, 26-Apr-04
Bootstrap Reg.
Charge Pump
Bootstrap Reg.
Charge Pump
V_DD
V_DD
23 _CAPA
21 _GTA
22
S_A
19 _CAPB
17 _GTB
18
S_B
20 _GBA
16 _GBB
15 _GND
−
+
13 _ILA+
−
+
14 _ILB+
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