3940

FULL-BRIDGE POWER

MOSFET CONTROLLER

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

8

Terminal Descriptions

CA/CB. High-side connection for bootstrap capacitor, positive

supply for high-side gate drive. The bootstrap capacitor is

charged to V

When the output swings high, the voltage on this terminal rises

with the output to provide the boosted gate voltage needed for n-

channel power MOSFETs.

RESET. Control input to put device into minimum power

consumption mode and to clear latched faults. Logic “1”

enables the device; logic “0” triggers the sleep mode. Internally

pulled down via 50 k

Ω resistor.

ENABLE. Logic “1” enables direct control of the output

drivers via the PHASE input, as in PWM controls, and ignores

the MODE and SR inputs. Internally pulled down via 50 k

Ω

resistor.

MODE. Logic input to set the current decay mode. Logic “1”

(slow-decay mode) switches off the high-side MOSFET in

response to a PWM “off” command. Logic “0” (fast-decay

mode) switches off both the high-side and low-side MOSFETs.

Internally pulled down via 50 k

Ω resistor.

PHASE. Motor direction control. When logic “1”, enables

gate drive outputs GHA and GLB allowing current flow from

SA to SB. When logic “0”, enables GHB and GLA allowing

current flow from SB to SA. Internally pulled down via 50 k

Ω

resistor.

SR. When logic “1”, enables synchronous rectification; logic

“0” disables the synchronous rectification. Internally pulled

down via 50 k

Ω resistor.

FAULT. Open drain, diagnostic logic output signal. When

logic “1”, indicates that one or more fault conditions have

occurred. Use an external pullup resistor to VREG5 or to digital

controller. Internally causes a coast when asserted. See also

Functional Description, next page.

IDEAD. Analog current set by resistor (12 k

Ω<R

to ground. In conjunction with LONG, determines dead time

LONG. When logic “1”, selects long dead time between GHx

and GLx transitions of same phase. When logic “0”, selects

short dead times. Internally pulled down via 50 k

Ω resistor.

GHA/GHB. High-side gate-drive outputs for n-channel

MOSFET drivers. External series gate resistors can control slew

rate seen at the power driver gate.

GLA/GLB. Low-side gate drive outputs for external, n-channel

MOSFET drivers. External series gate resistors can control slew

rate seen at the power driver gate.

GND. Common ground and dc supply returns. Exposed

thermal pad of LP package is NOT internally connected to

GND.

LSS. Low-side gate drivers’ return. Connects to the common

sources in the low-side of the power MOSFET bridge. It is the

reference connection for the short-to-battery monitor.

OVSET. A positive, dc level that controls the VBB overvoltage

trip point. Usually, provided from precision resistor divider

network between V

V

tively eliminating the overvoltage protection.

SA/SB. Directly connected to the motor terminals, these

terminals sense the voltages switched across the load and are

connected to the negative side of the bootstrap capacitors. Also,

are the negative supply connection for the floating, high-side

drivers.

VBB. Positive supply voltage. Usually connected to the motor

specified level, a fault will be asserted.

VDRAIN. Kelvin connection for drain-to-source voltage (short-

to-ground) monitor and is connected to high-side drains of the

MOSFET bridge. Also used to detect “open drain”.

VDSTH. A positive, dc level that sets the short-to-ground and

short-to-battery monitor threshold voltage. If the drain-source

voltage exceeds this level (after the dead time) during an “on”

state, a fault will be asserted.

CP1 [CP2]. Charge pump capacitor negative [positive] side. If

not using the charge pump, leave both terminals open.

VCP. Charge pump output for VREG13 input. If not using the

charge pump, connect this terminal to VBB.

VIN. Positive supply voltage for the V

Usually connected to VCP, the charge-pump output gate drive.

If not using the charge pump, connect VIN to VBB or other dc

supply greater than 11 V.

VREG13. High-side, gate-driver supply. If V

a specified level, a fault will be asserted.

VREG5. Regulated 5 V output for internal logic.