DRV595 Datasheet, PDF (13/24 Pages) Texas Instruments – 15V/±3A High-Efficiency PWM Power Driver

DRV595
www.ti.com
SLOS808 – DECEMBER 2012
INPUT IMPEDANCE
The DRV595 input stage is a fully differential input stage and the input impedance changes with the gain setting
from 9 kΩ at 36 dB gain to 60 kΩ at 20 dB gain. Table 1 lists the values from min to max gain. The tolerance of
the input resistor value is ±20% so the minimum value will be higher than 7.2 kΩ.
Table 2. Recommended Input AC-Coupling Capacitors
GAIN
20 dB
26 dB
32 dB
36 dB
INPUT IMPEDANCE
60 kΩ
30 kΩ
15 kΩ
9 kΩ
START-UP/SHUTDOWN OPERATION
The DRV595 employs a shutdown mode of operation designed to reduce supply current (Icc) to the absolute
minimum level during periods of non use for power conservation. The SDZ input terminal should be held high
(see specification table for trip point) during normal operation when the amplifier is in use. Pulling SDZ low will
put the outputs to Hi-Z and the amplifier to enter a low-current state. It is not recommended to leave SDZ
unconnected, because amplifier operation would be unpredictable.
GVDD SUPPLY
The GVDD Supply is used to power the gates of the output full bridge transistors. It can also be used to supply
the GAIN/SLV voltage divider. Decouple GVDD with a X5R ceramic 1 µF capacitor to GND. The GVDD supply is
not intended to be used as an external supply. It is recommended to limit the current consumption by using
resistor voltage dividers for GAIN/SLV of 100 kΩ or more.
BSP AND BSN CAPACITORS
The full H-bridge output stages use only NMOS transistors. Therefore, they require bootstrap capacitors for the
high side of each output to turn on correctly. A 220 nF ceramic capacitor of quality X5R or better, rated for at
least 16 V, must be connected from each output to its corresponding bootstrap input. (See the application circuit
diagram in Figure 13.) The bootstrap capacitors connected between the BSx pins and corresponding output pins
function as a floating power supply for the high-side N-channel power MOSFET gate drive circuitry. During each
high-side switching cycle, the bootstrap capacitors hold the gate-to-source voltage high enough to keep the high-
side MOSFETs turned on.
DIFFERENTIAL OR SINGLE-ENDED INPUTS
The differential input stage of the amplifier cancels any noise that appears on both input lines of the channel. To
use the DRV595 with a differential source, connect the positive lead of the signal source to the IN+ input and the
negative lead of the signal source to the IN– input. To use the DRV595 with a single-ended source, use a
voltage divider to bias IN- to 3.0V, and apply the single-ended signal to IN+.
Copyright © 2012, Texas Instruments Incorporated
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