12V to 5V DC-DC converter is outputting 7.5V
up vote
3
down vote
favorite
I recently bought these DC-DC converters. But when I apply 12VDC to the input I always observe 7.5V on the scope instead of 5V, I tried with a 680k load still 7.5V. But the datasheet says this is 12 to 5V converter.
What could be the reason?
dc-dc-converter
|
show 5 more comments
up vote
3
down vote
favorite
I recently bought these DC-DC converters. But when I apply 12VDC to the input I always observe 7.5V on the scope instead of 5V, I tried with a 680k load still 7.5V. But the datasheet says this is 12 to 5V converter.
What could be the reason?
dc-dc-converter
Which part number do you have? Also post a schematic of how you connect and measure it.
– Eugene Sh.
Dec 5 at 15:38
Connections are correct part no is TMV 1205S. See the answer below somehow if the load is light it cannot regulate.
– cm64
Dec 5 at 15:48
5
@cm64 I am glad the answer is providing what you need, but "Connections are correct" is not a valid response to the request of providing schematics in general. You believe it is correct, but you have a problem. So give the people trying to help you the information they request.
– Eugene Sh.
Dec 5 at 15:51
Max load is 200mA, so hook up something that gives better current. 1k through-hole or so.
– Lundin
Dec 5 at 15:53
The idle current is ~20mA. Try a 5mA load (1k) although it is supposed to work no load
– Tony EE rocketscientist
Dec 5 at 15:54
|
show 5 more comments
up vote
3
down vote
favorite
up vote
3
down vote
favorite
I recently bought these DC-DC converters. But when I apply 12VDC to the input I always observe 7.5V on the scope instead of 5V, I tried with a 680k load still 7.5V. But the datasheet says this is 12 to 5V converter.
What could be the reason?
dc-dc-converter
I recently bought these DC-DC converters. But when I apply 12VDC to the input I always observe 7.5V on the scope instead of 5V, I tried with a 680k load still 7.5V. But the datasheet says this is 12 to 5V converter.
What could be the reason?
dc-dc-converter
dc-dc-converter
edited Dec 5 at 15:55
asked Dec 5 at 15:34
cm64
197111
197111
Which part number do you have? Also post a schematic of how you connect and measure it.
– Eugene Sh.
Dec 5 at 15:38
Connections are correct part no is TMV 1205S. See the answer below somehow if the load is light it cannot regulate.
– cm64
Dec 5 at 15:48
5
@cm64 I am glad the answer is providing what you need, but "Connections are correct" is not a valid response to the request of providing schematics in general. You believe it is correct, but you have a problem. So give the people trying to help you the information they request.
– Eugene Sh.
Dec 5 at 15:51
Max load is 200mA, so hook up something that gives better current. 1k through-hole or so.
– Lundin
Dec 5 at 15:53
The idle current is ~20mA. Try a 5mA load (1k) although it is supposed to work no load
– Tony EE rocketscientist
Dec 5 at 15:54
|
show 5 more comments
Which part number do you have? Also post a schematic of how you connect and measure it.
– Eugene Sh.
Dec 5 at 15:38
Connections are correct part no is TMV 1205S. See the answer below somehow if the load is light it cannot regulate.
– cm64
Dec 5 at 15:48
5
@cm64 I am glad the answer is providing what you need, but "Connections are correct" is not a valid response to the request of providing schematics in general. You believe it is correct, but you have a problem. So give the people trying to help you the information they request.
– Eugene Sh.
Dec 5 at 15:51
Max load is 200mA, so hook up something that gives better current. 1k through-hole or so.
– Lundin
Dec 5 at 15:53
The idle current is ~20mA. Try a 5mA load (1k) although it is supposed to work no load
– Tony EE rocketscientist
Dec 5 at 15:54
Which part number do you have? Also post a schematic of how you connect and measure it.
– Eugene Sh.
Dec 5 at 15:38
Which part number do you have? Also post a schematic of how you connect and measure it.
– Eugene Sh.
Dec 5 at 15:38
Connections are correct part no is TMV 1205S. See the answer below somehow if the load is light it cannot regulate.
– cm64
Dec 5 at 15:48
Connections are correct part no is TMV 1205S. See the answer below somehow if the load is light it cannot regulate.
– cm64
Dec 5 at 15:48
5
5
@cm64 I am glad the answer is providing what you need, but "Connections are correct" is not a valid response to the request of providing schematics in general. You believe it is correct, but you have a problem. So give the people trying to help you the information they request.
– Eugene Sh.
Dec 5 at 15:51
@cm64 I am glad the answer is providing what you need, but "Connections are correct" is not a valid response to the request of providing schematics in general. You believe it is correct, but you have a problem. So give the people trying to help you the information they request.
– Eugene Sh.
Dec 5 at 15:51
Max load is 200mA, so hook up something that gives better current. 1k through-hole or so.
– Lundin
Dec 5 at 15:53
Max load is 200mA, so hook up something that gives better current. 1k through-hole or so.
– Lundin
Dec 5 at 15:53
The idle current is ~20mA. Try a 5mA load (1k) although it is supposed to work no load
– Tony EE rocketscientist
Dec 5 at 15:54
The idle current is ~20mA. Try a 5mA load (1k) although it is supposed to work no load
– Tony EE rocketscientist
Dec 5 at 15:54
|
show 5 more comments
2 Answers
2
active
oldest
votes
up vote
7
down vote
accepted
Try using a lower value resistor. With this one you get 11uA of current, which is close to open line. Try getting 10-20mA of load with resistor of say a couple of hundred ohms (200-300 should work) .
You are right I tried with 560 Ohm load it worked. I need to use So the load should sink min some amount of current? But it doesn't write in datasheet. At what output current do you think it starts to regulate properly?
– cm64
Dec 5 at 15:46
It is 5.6V for 560 Ohm
– cm64
Dec 5 at 15:49
@cm64 "Input current no load /full load. 5 Vin models 30 mA / 260 mA typ".
– Lundin
Dec 5 at 15:55
3
It's unusual for it not to be quoted in the datasheet, but as a rule of thumb many DC-DCs have a minimum load requirement of 10% of the rated max load current.
– pericynthion
Dec 5 at 16:04
2
It lists a load regulation variation of 10% for 20 to 100 percent load. So minimum load for regulation is 20%.
– Passerby
Dec 5 at 16:20
|
show 2 more comments
up vote
2
down vote
Since you didn't indicate much details in your analysis of your problem, I might be inclined to suggest ESD damage on the input. Something has attenuated the feedback that so that it overdriving the output.
The design input current is specified for NO LOAD.
Write to info@tracopower-solutions.com and
- 1) request tech support with all the details of your test of output Voltage vs R or I to full load.
- 2) request an RMA for return and FMEA failure report
Was it packaged in an antistatic bag>?
I received n a plastic tube and a normal plastic bag not anti-static. I bough 10 of them and I tried two of them they have the same behavior. But Im sure I didnt damage myself.
– cm64
Dec 5 at 16:27
THen follow the actions I listed after you do a range to full load tests and include your report
– Tony EE rocketscientist
Dec 5 at 16:35
@cm64 If they arrived with no anti-static protection, then anything could have happened in the post. They could easily be good from the factory and dead on arrival.
– AaronD
Dec 5 at 19:48
The datasheet lists characteristics under full load. This is normal behavior, all DC-DC converters have a minimum load below which they will be unable to regulate properly or be unstable. This is not a problem with the specific chip, it's just that normally Minimum Load is a clearly listed characteristic in the datasheet, but this datasheet doesn't list it.
– Drunken Code Monkey
Dec 5 at 21:30
1
If it is a DCM converter, it should operate fine with no load for which they only specify the input idle current and no mention of output voltage which we have to presume is nominal within tolerances. So call or write to the OEM..
– Tony EE rocketscientist
Dec 5 at 21:43
|
show 2 more comments
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
7
down vote
accepted
Try using a lower value resistor. With this one you get 11uA of current, which is close to open line. Try getting 10-20mA of load with resistor of say a couple of hundred ohms (200-300 should work) .
You are right I tried with 560 Ohm load it worked. I need to use So the load should sink min some amount of current? But it doesn't write in datasheet. At what output current do you think it starts to regulate properly?
– cm64
Dec 5 at 15:46
It is 5.6V for 560 Ohm
– cm64
Dec 5 at 15:49
@cm64 "Input current no load /full load. 5 Vin models 30 mA / 260 mA typ".
– Lundin
Dec 5 at 15:55
3
It's unusual for it not to be quoted in the datasheet, but as a rule of thumb many DC-DCs have a minimum load requirement of 10% of the rated max load current.
– pericynthion
Dec 5 at 16:04
2
It lists a load regulation variation of 10% for 20 to 100 percent load. So minimum load for regulation is 20%.
– Passerby
Dec 5 at 16:20
|
show 2 more comments
up vote
7
down vote
accepted
Try using a lower value resistor. With this one you get 11uA of current, which is close to open line. Try getting 10-20mA of load with resistor of say a couple of hundred ohms (200-300 should work) .
You are right I tried with 560 Ohm load it worked. I need to use So the load should sink min some amount of current? But it doesn't write in datasheet. At what output current do you think it starts to regulate properly?
– cm64
Dec 5 at 15:46
It is 5.6V for 560 Ohm
– cm64
Dec 5 at 15:49
@cm64 "Input current no load /full load. 5 Vin models 30 mA / 260 mA typ".
– Lundin
Dec 5 at 15:55
3
It's unusual for it not to be quoted in the datasheet, but as a rule of thumb many DC-DCs have a minimum load requirement of 10% of the rated max load current.
– pericynthion
Dec 5 at 16:04
2
It lists a load regulation variation of 10% for 20 to 100 percent load. So minimum load for regulation is 20%.
– Passerby
Dec 5 at 16:20
|
show 2 more comments
up vote
7
down vote
accepted
up vote
7
down vote
accepted
Try using a lower value resistor. With this one you get 11uA of current, which is close to open line. Try getting 10-20mA of load with resistor of say a couple of hundred ohms (200-300 should work) .
Try using a lower value resistor. With this one you get 11uA of current, which is close to open line. Try getting 10-20mA of load with resistor of say a couple of hundred ohms (200-300 should work) .
answered Dec 5 at 15:41
drdm
3064
3064
You are right I tried with 560 Ohm load it worked. I need to use So the load should sink min some amount of current? But it doesn't write in datasheet. At what output current do you think it starts to regulate properly?
– cm64
Dec 5 at 15:46
It is 5.6V for 560 Ohm
– cm64
Dec 5 at 15:49
@cm64 "Input current no load /full load. 5 Vin models 30 mA / 260 mA typ".
– Lundin
Dec 5 at 15:55
3
It's unusual for it not to be quoted in the datasheet, but as a rule of thumb many DC-DCs have a minimum load requirement of 10% of the rated max load current.
– pericynthion
Dec 5 at 16:04
2
It lists a load regulation variation of 10% for 20 to 100 percent load. So minimum load for regulation is 20%.
– Passerby
Dec 5 at 16:20
|
show 2 more comments
You are right I tried with 560 Ohm load it worked. I need to use So the load should sink min some amount of current? But it doesn't write in datasheet. At what output current do you think it starts to regulate properly?
– cm64
Dec 5 at 15:46
It is 5.6V for 560 Ohm
– cm64
Dec 5 at 15:49
@cm64 "Input current no load /full load. 5 Vin models 30 mA / 260 mA typ".
– Lundin
Dec 5 at 15:55
3
It's unusual for it not to be quoted in the datasheet, but as a rule of thumb many DC-DCs have a minimum load requirement of 10% of the rated max load current.
– pericynthion
Dec 5 at 16:04
2
It lists a load regulation variation of 10% for 20 to 100 percent load. So minimum load for regulation is 20%.
– Passerby
Dec 5 at 16:20
You are right I tried with 560 Ohm load it worked. I need to use So the load should sink min some amount of current? But it doesn't write in datasheet. At what output current do you think it starts to regulate properly?
– cm64
Dec 5 at 15:46
You are right I tried with 560 Ohm load it worked. I need to use So the load should sink min some amount of current? But it doesn't write in datasheet. At what output current do you think it starts to regulate properly?
– cm64
Dec 5 at 15:46
It is 5.6V for 560 Ohm
– cm64
Dec 5 at 15:49
It is 5.6V for 560 Ohm
– cm64
Dec 5 at 15:49
@cm64 "Input current no load /full load. 5 Vin models 30 mA / 260 mA typ".
– Lundin
Dec 5 at 15:55
@cm64 "Input current no load /full load. 5 Vin models 30 mA / 260 mA typ".
– Lundin
Dec 5 at 15:55
3
3
It's unusual for it not to be quoted in the datasheet, but as a rule of thumb many DC-DCs have a minimum load requirement of 10% of the rated max load current.
– pericynthion
Dec 5 at 16:04
It's unusual for it not to be quoted in the datasheet, but as a rule of thumb many DC-DCs have a minimum load requirement of 10% of the rated max load current.
– pericynthion
Dec 5 at 16:04
2
2
It lists a load regulation variation of 10% for 20 to 100 percent load. So minimum load for regulation is 20%.
– Passerby
Dec 5 at 16:20
It lists a load regulation variation of 10% for 20 to 100 percent load. So minimum load for regulation is 20%.
– Passerby
Dec 5 at 16:20
|
show 2 more comments
up vote
2
down vote
Since you didn't indicate much details in your analysis of your problem, I might be inclined to suggest ESD damage on the input. Something has attenuated the feedback that so that it overdriving the output.
The design input current is specified for NO LOAD.
Write to info@tracopower-solutions.com and
- 1) request tech support with all the details of your test of output Voltage vs R or I to full load.
- 2) request an RMA for return and FMEA failure report
Was it packaged in an antistatic bag>?
I received n a plastic tube and a normal plastic bag not anti-static. I bough 10 of them and I tried two of them they have the same behavior. But Im sure I didnt damage myself.
– cm64
Dec 5 at 16:27
THen follow the actions I listed after you do a range to full load tests and include your report
– Tony EE rocketscientist
Dec 5 at 16:35
@cm64 If they arrived with no anti-static protection, then anything could have happened in the post. They could easily be good from the factory and dead on arrival.
– AaronD
Dec 5 at 19:48
The datasheet lists characteristics under full load. This is normal behavior, all DC-DC converters have a minimum load below which they will be unable to regulate properly or be unstable. This is not a problem with the specific chip, it's just that normally Minimum Load is a clearly listed characteristic in the datasheet, but this datasheet doesn't list it.
– Drunken Code Monkey
Dec 5 at 21:30
1
If it is a DCM converter, it should operate fine with no load for which they only specify the input idle current and no mention of output voltage which we have to presume is nominal within tolerances. So call or write to the OEM..
– Tony EE rocketscientist
Dec 5 at 21:43
|
show 2 more comments
up vote
2
down vote
Since you didn't indicate much details in your analysis of your problem, I might be inclined to suggest ESD damage on the input. Something has attenuated the feedback that so that it overdriving the output.
The design input current is specified for NO LOAD.
Write to info@tracopower-solutions.com and
- 1) request tech support with all the details of your test of output Voltage vs R or I to full load.
- 2) request an RMA for return and FMEA failure report
Was it packaged in an antistatic bag>?
I received n a plastic tube and a normal plastic bag not anti-static. I bough 10 of them and I tried two of them they have the same behavior. But Im sure I didnt damage myself.
– cm64
Dec 5 at 16:27
THen follow the actions I listed after you do a range to full load tests and include your report
– Tony EE rocketscientist
Dec 5 at 16:35
@cm64 If they arrived with no anti-static protection, then anything could have happened in the post. They could easily be good from the factory and dead on arrival.
– AaronD
Dec 5 at 19:48
The datasheet lists characteristics under full load. This is normal behavior, all DC-DC converters have a minimum load below which they will be unable to regulate properly or be unstable. This is not a problem with the specific chip, it's just that normally Minimum Load is a clearly listed characteristic in the datasheet, but this datasheet doesn't list it.
– Drunken Code Monkey
Dec 5 at 21:30
1
If it is a DCM converter, it should operate fine with no load for which they only specify the input idle current and no mention of output voltage which we have to presume is nominal within tolerances. So call or write to the OEM..
– Tony EE rocketscientist
Dec 5 at 21:43
|
show 2 more comments
up vote
2
down vote
up vote
2
down vote
Since you didn't indicate much details in your analysis of your problem, I might be inclined to suggest ESD damage on the input. Something has attenuated the feedback that so that it overdriving the output.
The design input current is specified for NO LOAD.
Write to info@tracopower-solutions.com and
- 1) request tech support with all the details of your test of output Voltage vs R or I to full load.
- 2) request an RMA for return and FMEA failure report
Was it packaged in an antistatic bag>?
Since you didn't indicate much details in your analysis of your problem, I might be inclined to suggest ESD damage on the input. Something has attenuated the feedback that so that it overdriving the output.
The design input current is specified for NO LOAD.
Write to info@tracopower-solutions.com and
- 1) request tech support with all the details of your test of output Voltage vs R or I to full load.
- 2) request an RMA for return and FMEA failure report
Was it packaged in an antistatic bag>?
answered Dec 5 at 16:23
Tony EE rocketscientist
60.8k22192
60.8k22192
I received n a plastic tube and a normal plastic bag not anti-static. I bough 10 of them and I tried two of them they have the same behavior. But Im sure I didnt damage myself.
– cm64
Dec 5 at 16:27
THen follow the actions I listed after you do a range to full load tests and include your report
– Tony EE rocketscientist
Dec 5 at 16:35
@cm64 If they arrived with no anti-static protection, then anything could have happened in the post. They could easily be good from the factory and dead on arrival.
– AaronD
Dec 5 at 19:48
The datasheet lists characteristics under full load. This is normal behavior, all DC-DC converters have a minimum load below which they will be unable to regulate properly or be unstable. This is not a problem with the specific chip, it's just that normally Minimum Load is a clearly listed characteristic in the datasheet, but this datasheet doesn't list it.
– Drunken Code Monkey
Dec 5 at 21:30
1
If it is a DCM converter, it should operate fine with no load for which they only specify the input idle current and no mention of output voltage which we have to presume is nominal within tolerances. So call or write to the OEM..
– Tony EE rocketscientist
Dec 5 at 21:43
|
show 2 more comments
I received n a plastic tube and a normal plastic bag not anti-static. I bough 10 of them and I tried two of them they have the same behavior. But Im sure I didnt damage myself.
– cm64
Dec 5 at 16:27
THen follow the actions I listed after you do a range to full load tests and include your report
– Tony EE rocketscientist
Dec 5 at 16:35
@cm64 If they arrived with no anti-static protection, then anything could have happened in the post. They could easily be good from the factory and dead on arrival.
– AaronD
Dec 5 at 19:48
The datasheet lists characteristics under full load. This is normal behavior, all DC-DC converters have a minimum load below which they will be unable to regulate properly or be unstable. This is not a problem with the specific chip, it's just that normally Minimum Load is a clearly listed characteristic in the datasheet, but this datasheet doesn't list it.
– Drunken Code Monkey
Dec 5 at 21:30
1
If it is a DCM converter, it should operate fine with no load for which they only specify the input idle current and no mention of output voltage which we have to presume is nominal within tolerances. So call or write to the OEM..
– Tony EE rocketscientist
Dec 5 at 21:43
I received n a plastic tube and a normal plastic bag not anti-static. I bough 10 of them and I tried two of them they have the same behavior. But Im sure I didnt damage myself.
– cm64
Dec 5 at 16:27
I received n a plastic tube and a normal plastic bag not anti-static. I bough 10 of them and I tried two of them they have the same behavior. But Im sure I didnt damage myself.
– cm64
Dec 5 at 16:27
THen follow the actions I listed after you do a range to full load tests and include your report
– Tony EE rocketscientist
Dec 5 at 16:35
THen follow the actions I listed after you do a range to full load tests and include your report
– Tony EE rocketscientist
Dec 5 at 16:35
@cm64 If they arrived with no anti-static protection, then anything could have happened in the post. They could easily be good from the factory and dead on arrival.
– AaronD
Dec 5 at 19:48
@cm64 If they arrived with no anti-static protection, then anything could have happened in the post. They could easily be good from the factory and dead on arrival.
– AaronD
Dec 5 at 19:48
The datasheet lists characteristics under full load. This is normal behavior, all DC-DC converters have a minimum load below which they will be unable to regulate properly or be unstable. This is not a problem with the specific chip, it's just that normally Minimum Load is a clearly listed characteristic in the datasheet, but this datasheet doesn't list it.
– Drunken Code Monkey
Dec 5 at 21:30
The datasheet lists characteristics under full load. This is normal behavior, all DC-DC converters have a minimum load below which they will be unable to regulate properly or be unstable. This is not a problem with the specific chip, it's just that normally Minimum Load is a clearly listed characteristic in the datasheet, but this datasheet doesn't list it.
– Drunken Code Monkey
Dec 5 at 21:30
1
1
If it is a DCM converter, it should operate fine with no load for which they only specify the input idle current and no mention of output voltage which we have to presume is nominal within tolerances. So call or write to the OEM..
– Tony EE rocketscientist
Dec 5 at 21:43
If it is a DCM converter, it should operate fine with no load for which they only specify the input idle current and no mention of output voltage which we have to presume is nominal within tolerances. So call or write to the OEM..
– Tony EE rocketscientist
Dec 5 at 21:43
|
show 2 more comments
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Which part number do you have? Also post a schematic of how you connect and measure it.
– Eugene Sh.
Dec 5 at 15:38
Connections are correct part no is TMV 1205S. See the answer below somehow if the load is light it cannot regulate.
– cm64
Dec 5 at 15:48
5
@cm64 I am glad the answer is providing what you need, but "Connections are correct" is not a valid response to the request of providing schematics in general. You believe it is correct, but you have a problem. So give the people trying to help you the information they request.
– Eugene Sh.
Dec 5 at 15:51
Max load is 200mA, so hook up something that gives better current. 1k through-hole or so.
– Lundin
Dec 5 at 15:53
The idle current is ~20mA. Try a 5mA load (1k) although it is supposed to work no load
– Tony EE rocketscientist
Dec 5 at 15:54