HI Tony, Correct. Please provide the pcb layout.
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Forum post: RE: TPS61240: Output drop significantly with tiny loading
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Forum post: BQ25886: bq25886 issue
Part Number: BQ25886 When enable charge but battery is not connected. The waveform of bq25886 seems strange. The time axis is 40us. Why the SW switches for about 20us then stops for about 120us and repeat again? It may not be a charge and recharge process. Because the Deglitch time for recharge threshold and charge termination is about 250ms. It also may not be PFM. Because PFM at light load when battery is below minimum system voltage setting or charging is disabled. I watch the register. There is no fault and the charging state is CC fast charging. The Vsys and Vbat increases as charge voltage limit increases.
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Forum post: RE: LMZ31710: Schematic Verification for power modules of LMZ family
Hi Binayak, I have received your schematic and am in the process of reviewing it. I plan to provide a schematic review by the end of today. Regards, Jimmy
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Forum post: RE: TPSM84A22: Schematic Verification for power modules of TPSM family
Hi Binayak, I have received your schematic and am in the process of reviewing it. I plan to provide a schematic review by the end of today. Regards, Jimmy
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Forum post: RE: BQ24192I: Input current is large without battery
Hi, We are checking and will get back to you. Thanks, Ning.
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Forum post: RE: LMZM33604: Behaviour when VOUT==VIN
Hi, In order to get a stable 12V output, the input voltage should be after the knee in the voltage dropout Table 43 . Following the grey curve, your input voltage should be at least 12.6V for a stable 12V output. If you were to supply a 12V input at 4A loading, your output voltage will be regulated in drop out condition to 11.4V. Regards, Jimmy
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Forum post: BQ40Z50: How to understand Offset Error parameter?
Part Number: BQ40Z50 Hi, Per bq40z50 Technical Reference document, one of QMax Update disqualified conditions is Offset Error. I don't understand it well, could you please help me to understand it better: 1) "If Offset error accumulated during passed previous OCV reading exceeds 1% of Design Capacity, update is disqualified." Is this meaning, if the passed accumulated capacity is over 1% of design capacity, for example, passed capacity is 3380mah for a brand new battery pack, but design capacity configuration is 3200mah, then QMax Update is disqualified and QMax will not update? 2) "Offset error current is calculated as CC Deadband/Sense resistor value." Is this meaning how to configure Offset Error? Means Offset Error=CC Deadband/sense resistor value? Please clarify. Thanks, Joy
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Forum post: ISO5451-Q1: Noise issue on top gate signal
Part Number: ISO5451-Q1 I have the following: 4 switch 3-phase interleaved bi-directional buck boost converter (please refer to TMS320F280049: CMPSS query to implement peak current mode control of a 4 switch 3-phase interleaved bi-directional buck boost converter post for a diagram of my setup) 2 boards in total: Controller Board and Power Board 12 gate signals 12 ISO5451 gate drivers are on the Controller Board 12 IXYS IXDD609 buffers on the Power Board All 12 gate driver circuits are schematically identical The gate signal connections are connected via non-ideal long track traces from the Controller Board to the Power Board The switching frequency is 70kHz All gate signals to the ISO5451 are generated using the PWM module of the TMS320F280049 The TMS320F280049 is operating at a 100MHz clock frequency The tests were done with no inductor present and no supply voltage across the bridge Desat protection and miller clamp is part of the circuit and permanently enabled 22nF gate capacitance of each MOSFET 0 to 15V gate signals Out of the 12 gate drivers, I have a problem with one displaying the following characteristics causing a shoot-through. Green is the top gate signal Pink is the bottom gate signal I am baffled why I am observing sporadic 33.33MHz oscillations on the top gate when the bottom gate is high. This only occurs on only one of the 12 gate drivers. I have also bypassed the buffer with the same results.
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Forum post: RE: LMZ31710: Schematic Verification for power modules of LMZ family
Hi Binayak, I was able to review your schematic review that you've attached. For U115 schematic, were you planning on using the UVLO feature with a resistor divider? I only see a 49.9k pullup on the UINH/UVLO pin. The part has an internal pull up current source so that the part is enabled if left floating. If UVLO feature is not desired, you can remove the pull up resistor, saving you one extra component count. For all of the LMZ21701 schematics (PS 5, 6, 9, 10), I would recommend also adding a 0.1uF or 1uF bypass capacitor between VOS and AGND to provide more robustness for noise immunity since the VOS pin is a sensitive node that can impact stability and performance of the part if surrounded by external noise circuits. Additionally, please follow the PCB layout guideline especially for the dedicated isolated VOS trace highlighted in Figure 81 Layer 3 and keep the output feedback node as small as possible to prevent noise coupling through this path as well. Everything else in your schematic looks okay. Regards, Jimmy
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Forum post: RE: BQ24070: BQ24070 alternative with 3.8v System output
Hi Sergey, The BQ25606 should do the trick.
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Forum post: BQ24296M: F Acing issue in BQ24296M based desin
Part Number: BQ24296M HI, We are using below implementation in our design. Our goal is to get 5V@1.5A output . Case1: When 5V@1.5A Dc adapter is connected at VBUS ( When DC jack inserted, We are disabling the boost by disconnecting GND ) and bypass the 5V to output through PASS MOSFET Q1 and Q2 circuit. Case2: When DC jacked is not inserted . Battery is the power source and We get around 3.7V at BQ24296M Sys output. Which we boost through DC-DC TLV61048 and get 5V_Vout. Question 1 : When Battery is the input source and DC jack is not inserted, Why are we getting 4.6V at VBUS pin of BQ24296. Is this expected? We are also not getting 5V at output of boost ( with no load) we are getting around 4.6V only. Is this has anything to do with setting for OTG. We tried removing MOSFET Q1 and Q2 also from path but still getting voltage at VBUS pin of BQ24296 when Battery is the only input source.. Question2: Problem we are facing is that With no load also we are not getting 5V at Boost out put.when battery is the sole input source (Battery voltage at this time was 4.2V). But When 5V DC jack is inserted we get 5V at Vout. Any pointer to debug this issue will be helpful.. Note : we are using 3.7 /3250mAh Rechargeable Li Ion battery for this setup. Boost IC is : TLV61048E
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Forum post: BQ76920EVM: Boot button not working
Part Number: BQ76920EVM Hi, I am having trouble with the boot button on one of the bq76920EVM devices that we ordered. The dashboard shows the EV2400 is connected but the bq78350 is grayed out on bqStudio (using SMB). The bottom status bar also shows that there is "no acknowledgement from device". I have collected some voltage measurements as shown below. VC1: 3.769V VC2: 7.54V VC3: 11.31V VC4: 15.08V VC5: 18.85V BAT: 18.28V CAP1: 3.292V BAT+: 18.85V REGOUT: 2.523V I have also tried testing the bq76920EVM board using the evaluation software but still having problems with the boot button. Are there any troubleshooting steps that you suggest we should try to fix this board. Thanks, Justin
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Forum post: TPS82150: Buck converter functions correctly briefly then shuts off
Part Number: TPS82150 I just received my card card from manufacturing with the following buck converter using a TPS82150. I inspected the workmanship and it appears good. I did some static IRC checks to make sure there aren't any short circuits or cold solder joints and did not detect any issues that way either. Then I power it up by connecting TP21 and TP20 to a +12V power source with a current limit set at 1A. The output is completely unloaded. The supply powers up and outputs the correct voltage of 3.75V, measured at TP30. Power supply indicates less than 1mA of current draw on the +12V. (V25D supply is un-powered at this point) I then jumper in some downstream circuits, which consist of about couple of unloaded LDO regulators (LT1763). The current draw on the power supply rises to 2mA and the voltage output drops to about 3.73V or 3.74V. After about 5-10 minutes I look at it again and the output had dropped to ~3.3V and current at the power supply is up to 7mA. I remove the jumper to the downstream circuits and then the output drops to nearly zero (maybe ~110mV). At this point, the device seems to be fried as far as I can tell. Power cycling or anything else I try doesn't seem to help. The chip is not warm to the touch. This happened on Friday. Then I came in on Monday morning and decided to try again and pretty much repeated the same result (powered up correctly initially then seemed to fail). I tried Monday afternoon and the chip appears to still be dead. Can anyone offer suggestions on what the issue might be?
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Forum post: BQSTUDIO: My version of BQSTUDIO doesn't have the Chemistry icon.
Part Number: BQSTUDIO I'm running BQStudio v1.3.86 but there is no Chemistry icon to select. The program auto-detected my BQ27441GB and I have a Jauch single cell no.246521 battery, the datasheet says the cell used is LP504783JU 1s1p with a 2100 mAh rating. I've downloaded the Chemistry Updater sluc564fp.zip and extracted it to C:\ti\zips and restarted BQStudio, but still no Chemistry icon and there's no option to Update Chemistry under Help menu. What am I doing wrong?
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Forum post: BQ40Z80: Disabling FET_EN in the Field for Manual FET Control
Part Number: BQ40Z80 Hi, My customer would like to know if they can disable FET_EN in the field in order to control the FETs manually. My concern was that it disables charge and discharge per the TRM, but they have tested this with no issues per the use-case detailed below. Would there be any issues with FET_EN being disabled during normal operation in the field and using FET Toggle to turn them on/off?: Our scenario is that we would set FET_EN = 0, and then toggle the CHG and DSG FETs ON for normal operation. This way, when we receive the command to turn OFF one or the other, we can. The testing we have done so far (over current in charge and discharge) shows the FETs turn OFF and then recover in the normal fashion. The FET function from a safety standpoint appears to be the same whether FET_EN =1 or FET_EN = 0. What does disabling FW control mean if the function is the same either way we set FET_EN? We have our own system microprocessor that accepts commands from the outside world and transfers them to the 40z80. We can handle ChargingVoltage() and ChargingCurrent() on our own though this processor. Is there something else we are missing? Thanks, Antonio
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Forum post: TPS65131EVM-839: 3D model (STEP file) request for this board
Part Number: TPS65131EVM-839 Hi Team, We have a customer requesting for the 3D model (STP file) for TPS65131EVM-839. Please let me know if it is possible to request this file for this board. I will send the customer information offline if needed. Thanks! Jonathan
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Forum post: BQ2005: Reference Schematic
Part Number: BQ2005 Hello, Do we happen to have a reference schematic for BQ2005? It seems that the datasheet doesn't have a typical application circuit nor do we have an EVM or reference design that uses this chip. Thank you for any help!
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Forum post: LM2611: Which component values to adjust to avoid pulse-skipping mode?
Part Number: LM2611 I'm implementing a +5V to -20V regulator with an output current requirement around 10-20 mA. Because of the low current, I'm anticipating that pulse-skipping mode may kick in, which I want to avoid to decrease ripple. I've currently specified 10 uH for both the inductors and 1 uF for the Cuk capacitor. So my question is, if I detect pulse-skipping mode, which components can I try adjusting to mitigate this? For example, increasing one or both inductors, or decreasing the Cuk capacitor. Note that I'm currently awaiting the delivery of the prototype board and components, and asking for advice ahead of time.
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Forum post: BQ76940: Getting started with 12S design
Part Number: BQ76940 Hi, I'm getting started with a new battery management design. I am getting through a lot of the datasheet material and starting the schematic. I have a few questions. Here are a few details about my design: 1. We only need to monitor the cells and do balancing. I plan to use LTC7001 high side FET driver, so I'm planning not to use the CHRG/DISCH pins. I plan to use a dedicated microcontroller to read the status of the cells and determine when to break the circuit from charging. Is this okay? 2. I don't need the current sensing, is there any issue with leaving the sense pins floating? Or should I tie them to ground? 3. We plan to balance with only 20mA current, so I'm not planning to add external transitors. With 4.22V cell, I selected 105ohm resistors because there will be two of them in the discharge path, correct? So, 4.22V / (2*105) = 20mA. Ok? 4. I am mostly following figure 15 in the datasheet. I am confused by the little boxes near the cells that contain "VC10x" and "VC5x" respectively. Does this mean I should connect these nodes to the VC10x and VC5x pins? I think so, but not completely sure. 5. Could you quickly check the schematic so far? I found it sort of painful to follow the connections from figure 15, because I only have 12 cells. I think its correct, but wanted to check because some of the VC pins are shorted and it looks different from figure 15. Thank you, Erik(Please visit the site to view this file)
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Forum post: BQ24090: Not consistently signalling !CHG when charging
Part Number: BQ24090 Hi, We've been using the BQ24090 for years in a few designs and it's been pretty solid, with thousands of units in the field. With a new design variant I'm seeing some weird behavior that I'm having trouble understanding. The previous designs used a single 14500 cell, which is more frequently removed and charged in an external charger - the BQ24090 was mostly provided as a backup charging mechanism, so it's hard to say how prevalent this problem might have been in those versions. The version that's having trouble has five parallel 10440 cells and the BQ24090 is the only charging mechanism provided. The issue is that when USB power is connected, the IC always shows !PG but might not show !CHG, even though it seems to be charging. It seems to be dependent on the system load. The main load is an LED array whose current draw varies (often quickly) over a wide range from maybe 20 mA to about 2000 mA. When !PG goes low, the system halts the LED display and shows a single charging status LED (yellow for charging, green for charged/powered), and the whole array can be switched off for faster charging. Only !CHG often doesn't become active, despite the battery being in the normal chargeable range and current draw indicating that it's charging. The weird part is that the 'shutting down' signal for the LED array - a bright flash fading to black - will usually cause !CHG to respond. I think this has to be caused by either the current draw or the resulting voltage drop; I've ruled out a software problem by showing that it doesn't work if the master brightness of the array is turned down. ISET is 680R, ISET2 is low, PRETERM is 10k, and TS is 10k. The base system load (mostly MCU and WiFi hardware) is 80-110 mA. I've partly worked around it for now by adding a flash effect to signal when the USB cable has been connected. Obviously that's a kludge and not a good long-term solution, and it's not working completely. The system can go into its lowest power state, where the load (apart from the battery) is under 2 mA, and in the example on my workbench right now it's drawing 310 mA for charging. If I unplug the cable and plug it in again, it wakes up the MCU and does its "USB was connected" flash, but !CHG is high and no amount of flashing gets !CHG to go low again, until the USB cable is disconnected and reconnected. Again I ruled out a software issue by restarting the system from its power button; this uses exactly the same wakeup path as when !PG is asserted, so it's not a problem in the MCU GPIO configuration or anything. Everything is the same except that the charger hasn't been disconnected. The weird part is that charging seems to be proceeding normally. In the time I've had this test unit sitting on my bench, with the MCU in full shutdown, the current draw at the USB input has dropped to 260 mA and is still falling. I checked the !CHG pin state and it's at VCC, indicating the charger ought to be off, yet charging continues - it just dropped to 240 mA. What gives? This is causing customers some major headaches, since they're left without a way to reliably tell when the device has finished charging. I can try to get some more measurements, but my easy-to-probe desktop development version of the board isn't set up for the 5x10440 battery configuration and until I get something wired up I'm limited to testing in the production version, which is very hard to work with because of its size and form factor. I wanted to check here first and make sure I'm not missing something obvious. Thanks, Scott
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