JAJSEF7G December 2014 – February 2019 TPS659037
PRODUCTION DATA.
The TPS659037 device contains a SYNCDCDC input to sync DC-DCs with the external clock.
In forced PWM mode, SMPSs are synchronized on an external input clock (SYNCDCDC) whereas in Eco-mode or if the SYNCDCDC pin is grounded, the switching frequency is based on an internal RC oscillator. The clock generated from the internal RC oscillator can be output through GPIO5 to provide synchronization clock to external SMPSs. For PWM mode, a PLL is present to buffer the external input clock to create nine clock signals for the nine SMPSs with different phases.
The sync clock dither specification parameters are based on a triangular dither pattern, but other patterns that comply with the minimum and maximum sync frequency range and the maximum dither slope can also be used.
The ollowing figure shows ƒ(SYNC), the frequency of SYNCDCDC input clock and ƒSW, the frequency of PLL output signal.
When there is no clock present on SYNCDCDC pin, the PLL generates a clock with a frequency equal to ƒ(FALLBACK).
If a clock is present on SYNCDCDC pin with a frequency between ƒ(SAT_LO) and ƒ(SAT_HI), then the PLL is synchronised on SYNCDCDC clock and generates a clock with frequency equal to ƒ(SYNC).
If ƒ(SYNC) is higher than ƒ(SAT_HI), then the PLL generates a clock with a frequency equal to ƒ(SAT_HI).
If ƒ(SYNC) is smaller than ƒ(SAT_LO), then the PLL generates a clock with a frequency equal to ƒ(SAT_LO).