JAJSFO6G December 2015 – July 2024 TPS99000-Q1
PRODUCTION DATA
The TPS99000-Q1 contains two blocks that switch a relatively high amount of current. The first of these is the switching regulator which generates the voltages used by the DMD. The second is the integrated LED FET gate drivers.
The DMD regulator consists of the following pins of the TPS99000-Q1:
PIN | NAME | PEAK BOARD CURRENT |
---|---|---|
49 | DMD_VOFFSET | 800mA |
50 | DMD_VBIAS | 800mA |
51 | DMD_VRESET | 800mA |
52 | DRST_LS_IND | 800mA |
53 | DRST_PGND | 800mA |
54 | DRST_HS_IND | 800mA |
55 | VIN_DRST | 800mA |
56 | VSS_DRST | 800mA |
The value of 800mA for these pins relates to the peak current through the inductor due to the nature of the switching regulator architecture. The DC for these paths will be closer to the load current drawn by the DMD.
The high-current LED gate drive pins consist of the following TPS99000-Q1 pins:
PIN | NAME | PEAK BOARD CURRENT |
---|---|---|
42 | DRVR_PWR | 1A |
43 | S_EN1 | 1A |
44 | S_EN2 | 1A |
45 | R_EN | 100mA |
46 | G_EN | 100mA |
47 | B_EN | 100mA |
48 | VSS_DRVR | 1A |
Again, these values are for peak currents. In a typical application, these signals will be driven at a relatively low average frequency, about 10kHz. Assuming a FET gate capacitance of 2nF and that the FETS are driven at 6V, the magnitude of the DC draw of these signals is approximately:
For the power and ground signals, this number should be multiplied by the number of active FETs, giving a value of around 1.25mA.
In addition to these high current signals that are driven by the TPS99000-Q1, the LED driver electronics will likely have other circuits that handle the high currents required by the LEDs. These currents may be as high as 6A and therefore also requires special consideration by the layout engineer. As a guide for the PCB trace width requirements, the reader is referred to TI’s Application Note (SLUA366). The PCB trace widths used in TI’s design were:
SIGNAL GROUP | PCB TRACE WIDTH |
---|---|
DMD Regulator | 10 mils |
Gate Drivers | 5 mils |
LED Driver | 200 mils minimum, but maximize where possible to decrease power loses |