My question is in the relax mode,only VOK is clear at the time of qmax update,but in the learning cycle manual both VOK and R_DIS bits clear for QMAX updates,and VOK is not set at the beginning of discharge.

in our cycle resistance updates is not occurred. learning cycle failed.

please suggest me how to control VOK and R_DIS bits for the cycle.

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UCC27712-Q1: Gate Driver output current | Gate driver supply current | Decoupling capacitor current

December 13, 2019, 12:07 am

≫ Next: TLC59116: About saturation voltage

≪ Previous: BQ40Z50-R1: VOK and R_DIS

Part Number: UCC27712-Q1

Hi,

I have a couple of questions. Could someone please help me?

Question-1. I want to simulate a buck converter using this gate driver IC. Can I get the TINA model or the SPICE model of it?

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Scenario:

I have the gate driver and MOSFET whose gate charge is 26.5nC and let the charging time be 100ns or 50ns (Switching frequency = 500kHz, duty cycle = 0.3), based on which I get a I_average = 110 mA, let the peak current required is 2 A sourcing and 1.5 A sinking,

My voltage source can supply supply 10mA to the gate driver continuously.

If I design and use the decoupling capacitors at the gate IC supply, will the complete gate current be supplied by decoupling capacitors? Will there be any problem from the source voltage being loaded?

Please help me clarifying this detail.

Thanks,

Subbu.

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TLC59116: About saturation voltage

December 13, 2019, 12:17 am

≫ Next: TPS3701: External resistor

≪ Previous: UCC27712-Q1: Gate Driver output current | Gate driver supply current | Decoupling capacitor current

Part Number: TLC59116

Hello,

Regarding to saturation voltage on TLC59116, my customer is asking a question.

(Question)

What is the saturation voltage on LED channel?

(What is the voltage between input and output on saturation?)

For example, my customer will use 4 LEDs in each output channel.

Total LED output voltage is 14V(3.5V(Vf) x 4), channel output current is 20mA.

In this case, how much input voltage is needed for output voltage 14V?

(Of course, we need to consider the variation of Vf.)

Regards,

Tao_2199

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TPS3701: External resistor

December 13, 2019, 12:26 am

≫ Next: TPS61096A: TPS61096A

≪ Previous: TLC59116: About saturation voltage

Part Number: TPS3701

Our customer is considering to monitor with TPS3701 and would like to monitor about 43.8V with input voltage 48V.

In the above case, customer need to use high impedance resistor to divide the voltage.

Does TPS3701 have any limitation of the value for resistor ?

Thank you and best regards,

Michiaki

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TPS61096A: TPS61096A

December 13, 2019, 12:28 am

≫ Next: TPS61023: Taking leakage currents into accout

≪ Previous: TPS3701: External resistor

Part Number: TPS61096A

Hi,

I have two questions related to level shifters.

1. When device is disabled (EN=0V) and LVIx is logic high, what would be level on HVOx?

2. Electrical specs on page 5 list level shifter sourcing and sinking current to be 800uA while description on 7.7.4 on page 15 mention it to be 200uA. Which one is correct?

Thanks,

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TPS61023: Taking leakage currents into accout

December 13, 2019, 12:41 am

≫ Next: UCC21750-Q1: Enable time

≪ Previous: TPS61096A: TPS61096A

Part Number: TPS61023

Hello,

in my application I need a boost converter with a very low shutdown current, as the device will be in shutdown 90% of the time.

I found TPS61023 (and TPS61022, and others), but in the data sheet I see "Leakage current into VOUT pin" which is 1 uA typical and 3 uA maximum, while shutdown current is stated to be 0.1 uA typical and 0.2 uA maximum.

How should I take leakage currents into account? Should I consider 1.1 uA typical and 3.2 uA maximum total shutdown current (shutdown + leakage)?

On the other side, I see that leakage currents are taken with VOUT = 5 V, hence I am wondering whether the true disconnection option will droop VOUT to 0 V in shutdown, which should cut off the leakage current as well.

Can you please clarify?

Application conditions/requirements:

- VIN from a primary lithium battery (about 2.0 to 3.7 V)

- VOUT between 5.2 and 5.5 V

- IOUT about 1 mA (maybe 5-10 mA at maximum)

- high efficiency at light loads

- true output disconnection in shutdown

- lowest possible leakage current

- lowest possible shutdown current

Thanks in advance.

Regards,

Stefano

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UCC21750-Q1: Enable time

December 13, 2019, 12:43 am

≫ Next: TPS51220A: dual phase operation

≪ Previous: TPS61023: Taking leakage currents into accout

Part Number: UCC21750-Q1

Hi,

What is the opening delay of the PWM outputs when Enable in is set to low?
- Immediately 
- After a delay ??µS
- Synchronized with PWM state change

Thank you for the help.

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TPS51220A: dual phase operation

December 13, 2019, 12:55 am

≫ Next: LM5166: Swicthing Frequency with COT mode

≪ Previous: UCC21750-Q1: Enable time

Part Number: TPS51220A

Hello,

Could you let me know if TPS51220A can support dual phase operation.

best regards,

↧

LM5166: Swicthing Frequency with COT mode

December 13, 2019, 1:13 am

≫ Next: TLV758P: tlv758p thermal resistance

≪ Previous: TPS51220A: dual phase operation

Part Number: LM5166

Hi,

Would you response below my question ?

[Back Ground]

Currently, I am designing 3.3V non-isolated regulator with LM5166YDRCR(COT mode).

Then, I have simulated with LT spice to confrim swicthing behavior.

But , Observed switching frequency(SW pin) is 94.6KHz in spicte of Rt = 39.4kohm(According to foumula (4) in datasheet, It should be 478kHz ).

[Schematic]

Please see attached file.

[Question]

1) Why is swicthing frequecy 94.6kHz, not 478 Hz ?

2) Would you provide foumula to calculate swicthing frequency under this condition ?

It is urgently for me. Would you please provide your response as soon as possible ?

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TLV758P: tlv758p thermal resistance

December 13, 2019, 1:31 am

≫ Next: BQ34Z100-G1: BQ34Z100-G1

≪ Previous: LM5166: Swicthing Frequency with COT mode

Part Number: TLV758P

Dear team,

We recommend sot-23 TLV758p and TLV755 to customer. But customer wonder about the thermal resistance of those IC.

They will have 1.5W loss with 500mA load current but only last 1 second. Then repeat the short pulse after several hours. Will the LDO have some effects with the 1 second pulse? It will exceed 150 degree C.

Any other SOT23 LDO recommend for this?

Thanks.

Best regards,

Sammi

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BQ34Z100-G1: BQ34Z100-G1

December 13, 2019, 1:34 am

≫ Next: TPS25927: Load Capacitance

≪ Previous: TLV758P: tlv758p thermal resistance

Part Number: BQ34Z100-G1

I want to use the on GPCCHEM tool to determine the chem id for a battery pack connected to the bq34z100-g1.
The connected battery is a 6 cell, 4500mah LiPo battery. we use a scaling factor of 5.

I would like to know if the current values i will upload to the tool should also be scaled by 5 or if it should be the actual unscaled current?

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TPS25927: Load Capacitance

December 13, 2019, 1:49 am

≫ Next: LM5170EVM-BIDIR: LM5170 boost mode issue

≪ Previous: BQ34Z100-G1: BQ34Z100-G1

Part Number: TPS25927

Hello Team,

Could you help with our customer's question:

The customer using TPS259271 for the current control on the output of the Power Supply 12 V, 2 A.

The problem - The power supply does not start (protection is triggered) with a large capacitive load (several security devices/sensors, expansion units connected).
While the current consumption of the system is 1 A when they start from another power supply.

The customer triyng to adjust passive components in TPS259271 scheme.

R ilim selected correctly on 2.2 A. Increasing its value does not help.
C, which on dVdT was increased from 1000 pF to 1 μF, also does not help.

DESIGN PARAMETERS:
Input voltage range, VIN               = 14 V
Undervoltage lockout set point, V(UV) = 10,2 V
Load at start-up, RL(SU)               = 5 Ω
Current limit, IOL                     = 2.4 A
Maximum ambient temperature, TA        = 85°C

The question:
What is the maximum allowable Cout (Load capacitance)?
What should be the T dVdT value(Output Voltage Ramp Time) to achieve the maximum allowable Cout?

BR,
Ilya

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LM5170EVM-BIDIR: LM5170 boost mode issue

December 13, 2019, 1:59 am

≫ Next: UCC28950: Lmag

≪ Previous: TPS25927: Load Capacitance

Part Number: LM5170EVM-BIDIR

Hi Team,

My customer is testing LM5170 EVM-BIDIR boost mode function but doesn't get output voltage. the test process is below,

1. HV48VDC port is connect to DC load

2. J21 pin 1 & 2 closed

3. J4 pin 1 & 2 closed

4. J34 pin 1 & 2 closed

5. J35 pin 1 & 2 closed

6. J36 pin 1 & 2 closed

7. J37 pin 1 & 2 closed

8. J14 pin 1 & 2 closed

9. J15 pin 1 & 2 closed

10. J19 pin 1 & 2 closed

11. J29 pin 1 & 2 closed

12. J30 pin 1 & 2 closed

13. J28 pin 2 & 3 closed

14. J31 pin 1 & 2 connect to 5V

may we check what else we missed?

Thanks

Eddie Chou

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UCC28950: Lmag

December 13, 2019, 2:09 am

≫ Next: LM5145: LM5145 EVM the inductor core loss

≪ Previous: LM5170EVM-BIDIR: LM5170 boost mode issue

Part Number: UCC28950

Hi TI,

I have several questions as below.

Why Equation-30 for Lmag is with (1-Dtyp)? Should it be Dtyp? Because the Lmag current conduct during Dtyp.
Is it acceptable that the Lmag designed is 3.54mH while the min value calculated from Equation-30 is 17mH? It is not feasible to meet this at variable output conditions while having low winding loss of transformer.

Regards,

↧

LM5145: LM5145 EVM the inductor core loss

December 13, 2019, 2:17 am

≫ Next: UCD74120: Circuit Design UCD74120 and for UCD9244EP.

≪ Previous: UCC28950: Lmag

Part Number: LM5145

Hi Team，

Can you provide some the materials about CMLS136E-3R3MS（the inductor used in LM5145EVM）that can help to calculate its core loss?

Best Regards

Xing

↧

UCD74120: Circuit Design UCD74120 and for UCD9244EP.

December 13, 2019, 2:25 am

≫ Next: BQ27421-G1: Connecting/disconnecting battery from the IC

≪ Previous: LM5145: LM5145 EVM the inductor core loss

Part Number: UCD74120

Hi TI team,

In our design, we have two TMS320C6678 DSPs (D0 and D1). The variable core voltage (CVDDD) for each the DSPs consumes around 15A of current.

We are using two UCD74120 regulators designed for 20A of current - one for each core. They are connected with UCD9244-EP for smart reflex configuration.

I'm attaching the schematic of that portion. Kindly verify if the schematic for the UCD74120 and UCD9244EP are correct.

Thanks and Regards,
Binayak

(Please visit the site to view this file)

↧

BQ27421-G1: Connecting/disconnecting battery from the IC

December 13, 2019, 2:47 am

≫ Next: TPS61196: VIFBV and R10 selection

≪ Previous: UCD74120: Circuit Design UCD74120 and for UCD9244EP.

Part Number: BQ27421-G1

Hello, I'm working on a battery charger with SOH data output to advise the user when the battery needs to be replaced.

I'll be using a 18650 3,350mAh battery but it will be disconnected every day from the cell gauge and will be connected again when the battery needs to be charged. If I initialize the fuel gauge with the four values each time the battery is reconnected, will I have an accurate SOH after charging?

If this fuel gauge is not the solution, can you please recommend me another one?

Thanks in advance, Julian.

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