Part Number: TPS65217
Does the spike of the BAT pin as follows affect AC detection?
This spike is around 4V peak.
In reply to Paul Kundmueller:
In reply to TQ:
In reply to Jayanth Kruttiventi:
Datasheet says that 22ms power path deglitch is for voltage increasing? Does this mean that the deglitch only applies to voltage detection and not voltage REMOVAL detection?
I may be understanding this wrong.
In reply to Jesse Caparangca:
And could it be in someway related to this statement from the datasheet:
188.8.131.52 Shorted or Absent Battery
Can you confirm the time scale in the initial scope shot shared in the thread? Is it 5ms/div as it appears in the lower-right hand corner?
Can you provide a scope shot showing VBAT, SYS, and AC all on the same plot?
In reply to Brian Berner:
I would also be interested to know the value of Register 0x04 (CHGCONFIG1), bit D0 (CHG_EN) used in your system.
The default/reset value of this bit is '1', but you mentioned that there is no Battery in your system. In the absence of a battery, there may be measures we can take be writing values in the Register Map that will prevent your glitch on VBAT.
There is a whole section in the TPS65217 datasheet's Application section titled "10.2.2.2 Battery-Less/5-V Operation" (pages 75-76). Does your system match Case 1/2 or 3 more closely? How is your TS pin terminated?
Please refer to this section and verify your schematic is connected as shown in Figure 56 and read through the functional differences in the first column of Table 36, titled "POWER SUPPLIED THROUGH AC PIN"
Yes, the timescale is indeed 5ms/div in the first image.
Here's a scope shot of the AC, SYS, and BAT pin. For this image I had to disable the AC power path to perform a shutdown. The only board I have available for scoping has a damaged RTC section so shutdown by ALARM2 is unavailable. BAT pin behavior and other symptoms are similar though.
(Pink-AC; LightBlue-SYS; DarkBlue-BAT)
CHG_EN bit is left at its default enabled value (1). We've scoped and tried disabling this register before and still saw the same spike, although we did not study the differences in detail. The spike may be occurring a couple microseconds later or something like that. I think the spike will be there regardless of the charger settings. The spike we're seeing is when SYS is connected to BAT during shutdown and therefore following it all the way to its steady state.
We have our circuit configured similar to case 1/2 of section 10.2.2.2. Only difference I see is we don't have BAT and BAT_SENSE shorted to each other - all three are floating. TS is also left floating just as the left configuration in figure 56.
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