ADS1202 datasheet(16/25 Pages) TI

16 / 25 page

ADS1202

SBAS275B

www.ti.com

APPLICATIONS

Mode 0 operation in a typical application is shown in Figure

10. Measurement of the motor phase current is done via the

shunt resistor. For better performance, both signals are

filtered. R2 and C2 filter noise on the noninverting input

signal, R3 and C3 filter noise on the inverting input signal, and

C4 in combination with R2 and R3 filter the common-mode

input noise. In this configuration, the shunt resistor is con-

nected via three wires with the ADS1202.

The power supply is taken from the upper gate driver power

supply. A decoupling capacitor of 0.1

µF is recommended for

filtering the power supply. If better filtering is required, an

additional 1

µF to 10µF capacitor can be added.

The control lines M0 and M1 are both LOW while the part is

operating in mode 0. Two output signals, MCLK and MDAT,

are connected directly to the optocoupler. The optocoupler

can be connected to transfer a direct or inverse signal

because the output stage has the capacity to source and sink

the same current. The discharge resistor is not needed in

parallel with optocoupler diodes because the output driver

has the capacity to keep the LED diode out of the charge.

FIGURE 10. Application Diagram in Mode 0.

The DSP can be directly connected at the output of two

channels of the optocoupler, C28x or C24x. In this configu-

ration, the signals arriving at C28x or C24x are standard

delta-sigma modulator signals and are connected directly to

the SPICLK and SPISIMO pins. Being a delta-sigma con-

verter, there is no need to have word sync on the serial data,

so an SPI is ideal for connection. McBSP would work as well

in SPI mode.

When component reduction is necessary, the ADS1202 can

operate in mode 2, as shown in Figure 11. M1 is HIGH and

M0 is LOW. Only the noninverting input signal is filtered.

R2 and C2 filter noise on the input signal. The inverting input

is directly connected to the GND pin, which is simultaneously

connected to the shunt resistor.

The output signal from the ADS1202 is Manchester coded. In

this case, only one signal is transmitted. For that reason, one

optocoupler channel is used instead of two channels, as in

the previous example of Figure 10. Another advantage of this

configuration is that the DSP will use only one line per

channel instead of two. That permits the use of smaller DSP

packages in the application.

Ω

SENSE

Ω

5.1V

0.1

µF

ADS1202

0.1

µF

0.1

µF

10nF

IN+

IN–

MCLK

MDAT

GND

HV+

HV–

Floating

Power Supply

Gated

Drive Circuit

SPICLK

C28x

C24x

Optocoupler

SPISIMO

Gated

Drive Circuit

Power

Supply

ADS1202 Datasheet(PDF) 16 Page - Texas Instruments

ADS1202 Datasheet(HTML) 16 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Datasheet Download

Link URL