SLIS061D July 1998 – September 2015 TPIC6C595
PRODUCTION DATA.
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NOTE
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
The TPIC6C595 is a serial-in parallel-out, Power+LogicE 8-bit shift register with low-side switch DMOS outputs rating of 100 mA per channel. The device is designed for use in systems that require relatively moderate load power such as LEDs. The device contains a built-in voltage clamp on the outputs for inductive transient protection. Power driver applications include relays, solenoids, and other low current or medium-voltage loads. The following focuses on automotive cluster applications for the TPIC6C595.
The typical application of TPIC6C595 is automotive cluster driver. In this example, two TPIC6C595 power shift registers are cascaded and used to turn on LEDs in the cluster panel. In this case, the LED must be updated after all 16 bits of data have been loaded into the serial shift registers. MCU outputs the data to the serial input (SER IN) while clocking the shift register clock (SRCK). After the 16th clock, a pulse to the register clock (RCK) transfers the data to the storage registers. If output enable (G) is low, then the LEDs are turned on corresponding to the status word with ones being on and zeros off. With this simple scheme, MCU can use the SPI interface to turn on 16 LEDs using only two ICs as illustrated in Figure 14.
Table 1 shows the design parameters for this typical application.
DESIGN PARAMETERS | EXAMPLE VALUE |
---|---|
Vsupply | 9 V to 16 V |
V(D1), V(D2), V(D3), V(D4), V(D5), V(D6),V(D7), V(D8) | 2 V |
V(D9), V(D10),V(D11), V(D12), V(D13), V(D14),V(D15), V(D16) | 3.3 V |
I(D1), I(D2), I(D3), I(D4), I(D5), I(D6),I(D7), I(D8) | 20 mA when Vbattery is 12 V |
I(D9), I(D10), I(D11), I(D12), I(D13), I(D14),I(D15), I(D16) | 30 mA when Vbattery is 12 V |
To begin the design process, one must decide on a few parameters. The designer must know the following:
When Vsupply is 9 V, I(D1) = I(D2) = I(D3) = I(D4) = I(D5) = I(D6) = I(D7) = I(D8) = (Vsupply – V(Dx)) / Rx = 14 mA.
When Vsupply is 16 V, I(D1) = I(D2) = I(D3) = I(D4) = I(D5) = I(D6) = I(D7) = I(D8) = (Vsupply – V(Dx)) / Rx = 28 mA.
When Vsupply is 9 V, I(D9) = I(D10) = I(D11) = I(D12) = I(D13) = I(D14) = I(D15) = I(D16) = (Vsupply – V(Dx)) / Rx = 19.7 mA.
When Vsupply is 16 V, I(D9) = I(D10) = I(D11) = I(D12) = I(D13) = I(D14) = I(D15) = I(D16) = (Vsupply – V(Dx)) / Rx = 43.8 mA.
NOTE
If customer can accept the current variation when battery voltage is changing, they can connect to battery directly. If customer needs the less variation of current, they must use the voltage regulator as supply voltage of LED, or change to constant current LED driver directly.