Software Setup and Operation
It is recommended that the user press the 'READ' button at the top of the screen immediately after loading
the software to confirm that the software and cable connections are working properly. The message box at
the top right of the main panel (I2C Activity) displays all I
2
C activity. The message box at the bottom (USB
Bridge Connected) displays whether or not the USB-TO-GPIO connection is functional.
The software itself performs no calculations or computations and simply reads and writes to and from the
IC's registers through the I
2
C interface. Each register's bits can either be changed manually by changing
the boxes corresponding to each bit in the panel's bottom left half (REGISTERS section), or they can be
changed through the drop-down boxes and buttons in the rest of the panel. Some bits are reserved and
not writeable. These will not allow you to click on them to change their setting. For example, since the
TPS62360 does not have an operational register bit at bit 6 of registers 0x00h through 0x03h, the
TPS62360's main panel will not allow writes to those bits. The I
2
C bus speed is fixed at 100 kbps and this
is noted at the bottom of the screen.
Following any change to an individual bit, drop-down box, or button, the user must write the new values to
the registers by either clicking the 'W' button to the left of each affected register or by clicking the 'WRITE'
button at the top of the screen.
In order to reduce the amount of manual reading and writing required, the two drop-downs at the top left of
the screen have been provided to do this automatically. The 'Auto Read' drop down allows the option of
automatically reading all the registers at specific time intervals. The 'Write On Changes' drop-down allows
the option of automatically writing a change to the registers as soon as it is made in the software.
The TPS6236x datasheet is available via the 'Help' menu (Internet access is required). The datasheet
discusses the functionality of the various register bits, which is also briefly repeated here.
The drop-downs in the top left section of the software (SET0-SET3 section) correspond to registers 0x00h
thought 0x03h in the TPS6236x. These registers set the target output voltage and operating mode
(PFM/PWM or forced PWM). The output voltage on the TPS62360/2 is settable in 10 mV steps between
0.77V and 1.4V. The output voltage on the TPS62361B/5 is settable in 10 mV steps between 0.5V and
1.77V. The operating mode is either PFM/PWM, in which the IC is allowed to skip switching pulses at light
loads to keep the converting efficiency high, or forced PWM mode, in which the IC allows negative
inductor current at light loads to maintain a specific switching frequency and output noise. The TPS6236x
only runs at the settings of one of these four registers at a time. This operating register is selected by the
VSEL0 and VSEL1 jumpers and can be changed during operation.
The top right section of the software (CONTROLS section) contains the functionality of registers 0x04h
and 0x06h and some of the functionality of register 0x05h. The first 3 check boxes enable an internal
resistor on any of the EN, VSEL0, or VSEL1 pins. This resistor, which is internal to the TPS6236x, would
keep that pin in a defined state if it were left floating. The 'Disable Temperature shutdown feature' bit
disables the temperature shutdown internal to the IC, if selected. The 'Enable Active output capacitor
discharge at shutdown' forces the IC to actively discharge the output capacitor during shutdown. The first
drop-down sets the output voltage ramp timing and the final drop-down describes the ramp behavior when
the TPS6236x is changing its output voltage in PFM mode.
The bottom right section of the software (STATUS section) contains the remaining bits in register 0x05h.
The top indicator is green if the IC die temperature is low enough and turns red when the bit is set
corresponding to a die temperature exceeding 120
°
C typical. The indicator on the bottom turns red if
thermal shutdown has occurred. When this does occur, the TPS6236x will latch off and the temperature
must decrease below a hysteresis amount and the T
J
Temp shutdown bit needs to be reset by the user.
The button at the bottom of this section is provided for this purpose.
7
SLVU425A
–
April 2011
–
Revised July 2011
TPS6236xEVM-655
Copyright
©
2011, Texas Instruments Incorporated
