VNH7013XP-E H-Bridge Datasheet Questions - Page 1
Forum section: electronics / projects

author: t1d
author_rank: Super Contributor
timestamp: January 15, 2017, 02:24:53 am
content: I am having difficulty discerning information from the datasheet; it is really sparse. I have posted this same thread on the ST Forum, but there seems to be little activity, there, and I need to keep this project moving forward, as it is already needed.1) Where can I find additional information on this IC? (Other than the OrCad Model and Application Sheet.)2) What voltage can be used to activate/trip the H-Bridge gate to turn on the MOSFETs?Page 7/Tbl 3 of the DS states that the maximum gate/source voltage is 18v. But, Page 8/Tbl 5 of the DS states that the Gate Threshold Voltage is between 2v; minimum and 4v; maximum. Is it that the gate will definitely be tripped above 4v, but you should not exceed feeding it more than 18v?3) It appears that the Temp Sensor supply voltage is less than the gates?Per page 10, of the DS, the Chain Forward Voltage of the sensor is between 3.72v and 4.04v. If the Temp Sensor can only handle 4.04v, and I want to drive a PIC controller with 5v (this is typical, for the chip,) I guess I could add a separate VR, or a diode, to drop the voltage to power just the temperature sensor, but that seems an odd requirement. Am I working through this correctly?I am assuming that TSA+ is supplied voltage directly to that pin and that TSK- is tied to the controller pin that will read the temperature. Is that correct?4) The temperature reading is output by the H-Bridge as voltage. The acceptable operating temperature range is between -40*C and 175*C. The voltage is in micro-volts per degree Kelvin. I used this link to run the Kelvin math:http://www.rapidtables.com/convert/temperature/celsius-to-kelvin.htm...-40*C = 233.15*K * -8.1mV/K = -1888.515mV175*C = 448.15*K * -8.1mV/K = -3630.015mVBecause this is negative voltage, do I need to subtract it from the Temp Sensor's supplied voltage, to determine the voltage reading?And, as a follow up, if the Temp Sensor does require a unique voltage supply, shouldn't that be the voltage that I supply to the microcontroller's voltage reference pin?You can find the DS, here:http://www.st.com/content/ccc/resource/technical/document/datasheet/1b/41/37/d4/6d/b3/42/ee/DM00040392.pdf/files/DM00040…Thank you for your interest and help!Bump

author: t1d
author_rank: Super Contributor
timestamp: January 24, 2017, 05:01:41 am
content: I haven't found any answers, so I bumped this, to refresh it.

author: t1d
author_rank: Super Contributor
timestamp: February 02, 2017, 11:07:27 pm
content: I put in a support ticket to the technical department at ST. I never did hear from them, even after contacting customer service, to request a follow up. So, I am hurting for information. Any help would be greatly appreciated.An additional question has come to mind. Is the 72V/40A rating spread between the four MOSFETs, or is it per MOSFET? My thinking would be that it is for each individual MOSFET, but the pins on this device are so small, that I would be surprised to learn they could handle that much wattage.Thanks!

author: testian
author_rank: Regular Contributor
timestamp: February 03, 2017, 12:19:10 am
content: 2) Yes.3) You have to supply a constant current of 250µA to measure the voltage drop of the thermal sensor.Example:25 °C 250µA = 3.88Vfrom that if the temperature is changing by +50K (= 75°C)your measured voltage will change:3.88V + (-8.1mV/°K * 50K) = 3.475V

author: t1d
author_rank: Super Contributor
timestamp: February 03, 2017, 12:35:00 am
content: Quote from: testian on February 03, 2017, 12:19:10 amFirstly, Testian, thank you, so much, for your help. I am greatly appreciative.If you wouldn't mind, please continue to follow this thread, as I need all the help I can get. Hopefully, I have formed my questions well, but do not assume that I have great depth of understanding, as I am just a hobbyist.As for #3, I take it that I should add a constant current circuit, to supply 250uA, to the thermal sensor. I have seen many such circuits to power LEDs.As for the second part of #3, I take it that the reference voltage should be tied to this supply. Correct?Thank you, again.

author: t1d
author_rank: Super Contributor
timestamp: February 03, 2017, 12:43:42 am
content: I just noticed that I numbered the questions in the first post poorly.To confirm:a) The trip/trigger voltage is above 4v and below 18v?b) The thermal sensor needs a 250uA constant current supply?c) The reference pin of the controller for the thermal sensor needs to be tied to the voltage supply of b), above?Thank you.

author: amyk
author_rank: Super Contributor
timestamp: February 03, 2017, 11:32:42 am
content: Why that particular part? Why not a different one, especially if ST seem completely disinterested in you using it?

author: langwadt
author_rank: Super Contributor
timestamp: February 03, 2017, 02:31:38 pm
content: why that particular part? it is just four "dumb" mosfets and a few diodes to measure temperature, you'll need gate drivers and have to handle protectionwhy not use one of the numerous parts that does the same job with everything build in?

author: t1d
author_rank: Super Contributor
timestamp: February 07, 2017, 10:53:46 pm
content: Here is the reply form ST. I think it is complete and well explained. Thanks to ST, for their support!!!I have from the email notification different questions than what is below. I will endeavor to answer all of them here.1) Where can I find additional information on this IC? (Other than the OrCad Model and Application Sheet.)A. All of the information you need is contained in the datasheet.2) What voltage can be used to activate/trip the H-Bridge gate to turn on the MOSFETs?A. This device is basically 4 MOSFETS in a single package.. There is no â€œtripâ€. There is a gate voltage threshold. For MOSFETs that is the Gate-Source voltage at which the MOSFET starts conducting. It is not fully enhanced. It just starts turning on at some point between 2V and 4V. To fully enhance the MOSFET we recommend a Gate-Source voltage of 10V. This is the voltage where the on resistance is specified.Page 7/Tbl 3 of the Datasheet states that the maximum gate/source voltage is 18v. But, Page 8/Tbl 5 of the Datasheet states that the Gate Threshold Voltage is between 2v; minimum and 4v; maximum. Is it that the gate will definitely be tripped above 4v, but you should not exceed feeding it more than 18v?A. The maximum voltage is limited to 18V because that is where the gate oxide begins to break down. So, you will want to drive the Gates such that the voltage between the gate and source is above 10V but below 18V2) It appears that the Temperature Sensor supply voltage is less than the gates?A. The temperature sensor is basically a string of Diodes. The Diode forward voltage has a fairly stable temperature coefficient. You do not drive this with a voltageâ€¦ You drive this with a small current. We rate the diode forward voltage at 250uA. This is enough to bias the diode junction while not incurring self heating.Per page 10, of the Datasheet, the Chain Forward Voltage of the sensor is between 3.72v and 4.04v. If the Temperature Sensor can only handle 4.04v, and I want to drive a PIC controller with 5v (this is typical, for the chip,) I guess I could add a separate Voltage Regulator, or a diode, to drop the voltage to power just the temperature sensor, but that seems an odd requirement. Am I working through this correctly?A. Again, you do not drive this with a voltage. It is driven with a currentâ€¦ ST recommends 250uA. Then you measure the resulting voltage.I am assuming that TSA+ is supplied voltage directly to that pin and that TSK- is tied to the controller pin that will read the temperature. Is that correct?A. No, the TSA+ is the anode of the diode string this is where you supply the 250uA (not a voltage). TSK- is the cathode of the diode string and should be tiesd to signal ground. You injext the 250uA into TSA+ and measure the voltage from TSA+ to TSK- to determine the junction temperature of the high side MOSFETS.3) The temperature reading is output by the H-Bridge as voltage. The acceptable operating temperature range is between -40*C and 175*C. The voltage is in micro-volts per degree Kelvin. I used this link to run the Kelvin math:http://www.rapidtables.com/convert/temperature/celsius-to-kelvin.htm...-40*C = 233.15*K * -8.1mV/K = -1888.515mV175*C = 448.15*K * -8.1mV/K = -3630.015mVBecause this is negative voltage, do I need to subtract it from the Temperature Sensor's supplied voltage, to determine the voltage reading?A. There is no difference between mV/K and mV/C. They are the same. The difference between Kelvins and Centigrade is the starting pointâ€¦ Kelvin starts at absolute 0. Centigrade starts at the freezing point of water. The datasheet gives you a reference point at 25C. The variation from that point changes by -8.1mV/C.And, as a follow up, if the Temperature Sensor does require a unique voltage supply, shouldn't that be the voltage that I supply to the microcontroller's voltage reference pin?A. See previous responsesThis H-Bridge is rated as 72 volts @ 40 amps. Is that the ratings for each of the individual MOSFETS? Or, should those numbers be divided between the four MOSFETS, making them 18 volts @ 10 amps, each? It is hard to imagine that the tiny pins can carry such a high wattage.The 72V maximum rating is when the bridge is off and dormant. The individual MOSFETs have breakdown voltage, V(BR)DSS, of 36V (see table 4).The bridge is not rated at 72V and 40A. This is the absolute maximum rating. Any excursion above these ratings may permanently damage the device. Absolute maximum rateings are not where you determine the capability of a deviceâ€¦ any device.What limits the use of this device, as well as all other power devices, is the heat dissipation while in use. Power dissipation in the switch is based on the Rds(on) (table 5) multiplied by the square of the load current. If you are PWMming at any significant frequency switching losses should also be included. That power is then dissipated through the circuit board. Depending on the circuit board layout the ability to dissipate that heat varies (see section 3.1).Regards,STMicroelectronics Support Center