Re: Supply Current of LPC213x
2005-02-03 by Owen Mooney
Well - this all rips my socks!! I put a post in a few weeks ago asking about power consumption of the LPC213x series for use in a data logger. Robert said then about 150uA. This was too much for a logger with a 10 year battery life on a Lithium. So - I have just done a layout using a PIC ! Now I understand the latest run of chips is about 50uA. Quite some difference, and worth while ripping the PIC out of the circuit and putting in an LPC2132 Please confirm. For an LPCLPC213x series microprocessor with 32768 Xtal running powern consumption is 50+18uA in Powerdown mode and when I wake up from an external interupt I can read the current Xtal osc value in the CTC register ? If so I will rip out the PIC anbd use one of these - even if I have to go to a C size cell. What is the expected power consumptin of these devices in future production runs? Owen Mooney Date: Wed, 02 Feb 2005 14:29:09 -0000 From: "tah2k" <tah2k@...> Subject: Re: Supply Current. Lots additional information I didn't see an explanantion for the 350uA sleep current or my questions 1 and 2 concerning the I/O. Do I need to try a new device on the evaluation board? 50uA sleep current is perfect, 140uA is tolerable, and 350uA is a show stopper. --- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@y...> wrote: >> >> Tim, >> >> I guess the 350 mA (the "m" should be a "u")was a typo. What you >> measured in power down for the RTC is correct between 15 and 20 > > uAs. >> Logic in this process needs to run at 1.8V \ufffd 10 %. A pin like > > Vbat >> needs a wider spec and a different voltage. The spec for Vbat will > > be >> significantly extended to probably 2.0V-3.6V (characterization is >> ongoing). To not damage the logic we need to convert the external >> voltage down to 1.8V The converter uses most of the 18 uAs you > > measured. >> The higher current during active mode is due to an chip failure on > > the >> first devices, which have been used to build evaluation boards. New >> devices will not draw higher current during active mode on Vbat but >> still draw the 15-20 uAs. >> >> THIS INFORMATION IS SPECIFIC FOR THE LPC2130 series >> Power down current on the first devices was measured around 140 > > uAs, >> keeping all the RAM intact. Our latest lot with some fixes brings > > this >> value down to approx 50 uAs. >> While this value might be too high for some of you, it might be > > good >> enough for others and it is for sure a lot better than the previous >> option to go into idle mode using the RTC. >> >> Comparing an ARM build in 0.18um process to an AVR, PIC, MSP430 or > > you >> name them is really comparing apples to oranges. New processes > > enable >> the chip vendors to put more memory and build faster devices but > > the >> leakage goes up. >> >> In the end the only thing I can tell you, this is as good as it > > gets >> right now. Will let everybody know if we find ways to improve the >> power down behavior. Keep in mind that active current is as low or >> lower than an 8-bit running at the same clock rate delivering a lot >> less performance. >> >> Regards, Robert >> >> --- In lpc2000@yahoogroups.com, "tah2k" <tah2k@y...> wrote: > > >>> > >>> > I finally got to the point of shutting down the LPC2138 on the >> >> Keil >>> > development board. Battery life is critical to my application, >>> > therefore I need to verify the sleep specification. At room >>> > temperature, with all I/O configured as input except for JTAG, I >> >> am >>> > measuring 350mA just on the VDD pins! Far from 10uA. All >> >> peripheral >>> > clocks are disabled except the RTC which is configured to use >> >> the >>> > 32kHz. >>> > >>> > FYI: >>> > Vbat: ~31uA while processor is on, ~18uA during powerdown. (Just >> >> for >>> > the RTC?!?!) >>> > >>> > When it comes to sleep current issues, the first thing vendors >>> > usually question is the I/O state. The following are the >> >> relevant >>> > register values: >>> > >>> > PINSEL0: 0x0 >>> > PINSEL1: 0x0 >>> > PINSEL2: 0x4 >>> > >>> > IODIR0: 0x0 >>> > IODIR1: 0x0 >>> > >>> > IOPIN0: 0x7EFFF7F8 >>> > IOPIN1: 0x03FF0000 >>> > >>> > I'm puzzled about the I/O: >>> > 1.) The IOPIN register does not necessarily reflect the state of >> >> the >>> > I/O line. For example, P0.4 is not connected on the Keil board. >>> > Since this pin is configured as an input, I would suspect the >>> > voltage on the pin to reflect the internal pullup, but it >> >> measures >>> > 0V. Even more puzzling, IOPIN0 states this input is high. Go >> >> figure. >>> > >>> > 2.) Another concern: P0.31 is not connected, but configured as >> >> an >>> > input. If I measure the pin voltage it is 2.3 instead of 3.3V. >> >> This >>> > is also true for P1.16-23 and P1.24-25. Could I be leaking >> >> current
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>>> > through the pullup resistor? >>> > >>> > -Tim >> >> >> --- snip ----- > >