Cypress Semiconductor CY8CKIT-015, Manual

Page: 15 / 36

CY8CKIT-015 PSoC 1 Power Supervision Kit Guide, Doc. # 001-81218 Rev. ** 15
Example Project
Figure 3-7. PSoC 1 Power Supervision Functional Diagram
Note that the EBK hardware supports up to four secondary regulator circuits. The PSoC 1 Power
Supervisor solution can be easily extended to support up to eight secondary regulator circuits.
3.4 Technical Details
3.4.1 Voltage Sequencing
Voltage sequencing is a major function of any power supervisor IC. The supply voltages to different
sub-systems of a complex system are required to be sequenced depending on operating conditions,
such as power up, power down, and fault conditions to ensure proper operation of all the devices. As
the system becomes more complex, the number of different supply voltages in a single system
increases. Therefore, an accurate and reliable power sequencing solution is required.
When powering up the system, each of the voltage regulators needs to be powered one after the
other in a sequence with programmable delays between each of them. During sequencing, the con-
troller enables the voltage regulator, monitors its rail for the voltage level, and proceeds to the next
rail only if the voltage level is within the user-defined UV/OV range. If a power rail does not reach the
expected voltage level, the controller must indicate a sequencing fail.
This implementation uses the following resources:
■
A 16-bit counter for generating user-defined delays. Two digital blocks of PSoC 1 are used to cre-
ate a 16-bit counter with a 50-kHz internally generated clock as the time base, which gives the
maximum counting time interval of 1.31 seconds before overflowing. The API provided can be
used to generate a time delay from 1 to 1.31 seconds in steps of 1 msec.
■
Four GPIOs to enable or disable four voltage regulators on the CY8CKIT-035 board.