Is "KE9H" is MCP73831 ?

[vinodstanur]

Hi,
I ordered few MCP73831 lithium polymer/ion battery charging IC from element14. But none of those chips are working and then I tried to read the characters written on the top of the ic and it is "KE9H". Now I am confused if it is the same part or not...

Does any one have any similar issue?

 

[tpetar]

You have MCP73831T-2ATI/OT with code KEnn. Where nn is Alphanumeric traceability code.

Also see page 21 in datasheet **broken link removed**


I use MCP73832T-2ACI/OT and works great.

 

[vinodstanur]

You have MCP73831T-2ATI/OT with code KEnn. Where nn is Alphanumeric traceability code.

Also see page 21 in datasheet **broken link removed**


I use MCP73832T-2ACI/OT and works great.

Hi,
What is the difference between MCP73831T-2AT1/OT and MCP73832T-2ACI/OT?

 

[tpetar]

Re: Is "KE9H" is MCP73831 ?

Hi,
What is the difference between MCP73831T-2AT1/OT and MCP73832T-2ACI/OT?

The charge status output of the MCP73831 has three different states: High (H), Low (L), and High-Impedance (Hi-Z). The charge status output of the MCP73832 is open-drain, and, as such, has two different states: Low (L), and High-Impedance (Hi-Z). The charge charge status output can be used to illuminate 1, 2, or tri-color LEDs. Optionally, the charge status output can be used as an interface to a host microcontroller.




AC and AT difference :



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If you have trouble, try to increase 4,7uF to 10uF, and dont use some old electrolytic capacitors, I use 0805 ceramic 4,7uF.

 

[vinodstanur]

Hi, now I tried 4th IC from the package and it is working!.... But the IC is getting heated little bit when I am providing 5v.
I am charging 500mA li po battery at 218mA current. (PROG 4.7k resistor).
Is it natural that the chip will get heated little bit heated?

 

[tpetar]

Yes its ok to heat. You should make some heatsink on PCB for IC according to datasheet. Make additional copper area connected to IC pins, even with double sided PCB connected over thermal vias.

PowerDissipation = (VDDmax – VPTHmin) × IREGmax

Where:
VDDMAX = the maximum input voltage
IREGMAX = the maximum fast charge current
VPTHMIN = the minimum transition threshold voltage

Power dissipation with a 5V, ±10% input voltage source is:
PowerDissipation = (5.5V – 2.7V) × 550mA = 1.54W

For optimum voltage regulation, place the battery pack as close as possible to the device’s VBAT and VSS pins. This is recommended to minimize voltage drops along the high current-carrying PCB traces. If the PCB layout is used as a heatsink, adding many vias in the heatsink pad can help conduct more heat to the backplane of the PCB, thus reducing the maximum junction temperature. Figures 6-4 and 6-5 depict a typical layout with PCB heatsinking.




I charging phones Li-Ion/Li-Po batteries and Li-Ion 18650 with this, and Ic is real warrior. :smile:

;-)

 

[vinodstanur]

Hi,
While testing the chip right now, I connected two 4.7K in series to reduce the charging current to 106mA. Then I touched the PROG pin and the chip got burned...

 

[tpetar]

Charging current is set with resistor (2K on illustration) with formula given in datasheet :

Ireg (mA) = 1000V / Rprog (in KΩ)

According to 2x4,7KΩ its 9,4KΩ and that set current to 106mA.



IC is connected to copper on PCB ?

You must use capacitors!

Check input voltage!

 

[vinodstanur]

Re: Is "KE9H" is MCP73831 ?

No today only I got the IC chips so I am testing by connecting small wires to the IC ;-)

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Layout is very very important for these type of chips right?

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Also now while testing, I am not connecting any parallel capacitors (recommended 4.7uF) near to the Vdd and Vbat.

 

[tpetar]

Re: Is "KE9H" is MCP73831 ?

Better connect this small IC to copper, even when testing, to prevent some internal circuit damaging.

I'm very satisfied with this IC, its cheap and design is very easy and small.

Also IC have Reverse-Blocking Protection. The MCP73831/2 provide protection from a faulted or shorted input. Without the protection, a faulted or shorted input would discharge the battery pack through the body diode of the internal pass transistor.

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Layout is very very important for these type of chips right?

Shape of copper area on PCB is not immportant, but you must provide enough copper as heatsink connected to IC pin for cooling purposes.

Also now while testing, I am not connecting any parallel capacitors (recommended 4.7uF) near to the Vdd and Vbat.

Use capacitors always. External Capacitors - The MCP73831/2 are stable with or without a battery load. In order to maintain good AC stability in the Constant-Voltage mode, a minimum capacitance of 4.7 μF is recommended to bypass the VBAT pin to VSS. This capacitance provides compensation when there is no battery load. In addition, the battery and interconnections appear inductive at high frequencies. These elements are in the control feedback loop during Constant-Voltage mode. Therefore, the bypass capacitance may be necessary to compensate for the inductive nature of the battery pack. Virtually any good quality output filter capacitor can be used, independent of the capacitor’s minimum Effective Series Resistance (ESR) value. The actual value of the capacitor (and its associated ESR) depends on the output load current. A 4.7 μF ceramic, tantalum or aluminum electrolytic capacitor at the output is usually sufficient to ensure stability for output currents up to a 500 mA.



You can see all relevant information in product datasheet.

 

[udhay_cit]

I am using MCP73831 & the marking on the device is KD9Q.... Ic warm little but its not an issue... My circuit....

 

[vinodstanur]

Re: Is "KE9H" is MCP73831 ?


Hi I made the pcb just now... (photo)

Still it is not working properly... Supply current some time increases to very large value and the chip is getting damaged... This happened after connecting two 4.7 k in series to prog.... Will long resistor pins exposed to air make any problem to the chip? Seems to be the PROG pin is very sensitive...

 

[tpetar]

Re: Is "KE9H" is MCP73831 ?

I use 1% 0805 resistors and all are very tiny and close to IC pins. I didnt have problems. I using MCP73832 which is almost the same with your IC.

I dont see capacitors on this picture, except one 470uF 25V outside PCB.
Uh sorry I zoom picture I see one ceramic.

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What is input voltage ? and if you use switcher put one 100nF on input before 4,7uF.

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Your current configuration is for 212mA and its in range of IC.

Check input voltage or try some other PSU, try USB source. Check value of output capacitor to be minimum 4,7uF, and put on input minimum 4,7uF according to datasheet.

 

[vinodstanur]

I THINK MY PROBLEM IS SOLVED!!!!....

After connecting a capacitor (0.1uF) near to the Vdd Gnd it become stable!
Thanks Tpetar...

 

[tpetar]

Probably switcher have lots of ripples and spikes.

I'm glad to see successfully story.

 

[vinodstanur]

Yeah I checked it with DSO and it is having spikes...
Can you suggest a good pure regulator for 0 to 30v and 5A..
Which brand you are using? Mine is ATTEN APS300GSi

 

[vinodstanur]

If I am using this charging IC, then no need to remove the charging power if the battery is fully charged, Right?
Also the maximum charging current for a 500mA li po battery is 250 mA, am I right?

 

[tpetar]

Re: Is "KE9H" is MCP73831 ?

I dont know how but last my post is duplicated. Post was #17 and I try to delete #18 duplicate copy after that both gone. This is restored #17 post :


I use linear LM338K regulator its indestructible predator. :smile:


For powering finalized devices I use 3,7V Li-Ion with StepUp IC to 5V or 12V, and of course MCP73832 charging IC, all inside device small and compact. For power input connector I use mini USB.


Under Chinese expansion brand names lose meanings. I stricly look price, benefit and design simplicity. Quality of product must be personaly tested on each received package of parts.

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I recently have one problem with 7-seg led display, for project I use small switcher mains adapter 220V to 5V, and I have lots of problems with flickering of displays. When I put small adapter on scope, I'm shocked to see spikes near 40V.

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I often use this IC, you can check it :

MCP1640
https://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en547080

If I am using this charging IC, then no need to remove the charging power if the battery is fully charged, Right?

Yes MCP73831-2 turn of charging process when battery is full, and retrigger charging cycle on some level of discharge state 66%-75% depends from part number, see datasheet.

Charging Termination
The charge cycle is terminated when, during Constant-Voltage mode, the average charge current diminishes below a percentage of the programmed charge current (established with the value of the resistor connected to the PROG pin). A 1 ms filter time on the termination comparator ensures that transient load conditions do not result in premature charge cycle termination. The percentage or ratio of the current is factory set. Refer to Section 1.0 “Electrical Characteristics” for charge termination current options and the ”Product Identification System” for standard options.
The charge current is latched off and the MCP73831/2 enter a Charge Complete mode.

Automatic Recharge
The MCP73831/2 continuously monitor the voltage at the VBAT pin in the Charge Complete mode. If the voltage drops below the recharge threshold, another charge cycle begins and current is once again supplied to the battery or load. The recharge threshold is factory set. Refer to Section 1.0 “Electrical Characteristics” for recharge threshold options and the ”Product Identification System” for standard options.

Reverse-Blocking Protection
The MCP73831/2 provide protection from a faulted or shorted input. Without the protection, a faulted or shorted input would discharge the battery pack through the body diode of the internal pass transistor.

Also the maximum charging current for a 500mA li po battery is 250 mA, am I right?

Maximum charging current 500mAh Li-Po is one step before battery start to heat and start to expand. :smile:
Small phone batteries (up to 1200mAh) I charge with max 100mA, 18650 Li-Ion in two steps low 150mA and fast 400mA.

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I again see double posts, I must stop drinking Coca-Cola. :smile:

 

[vinodstanur]

So suggest me a charging current for 500mAh lipo battery...
I am planning to set 250mA as the charging current and I guess it will get charged with in 2 hours...

 

[tpetar]

Re: Is "KE9H" is MCP73831 ?

I personally avoid to stress batteries with higher charging rates.
Charging current depends also a lots from quality of battery, model, and manufacturer charging recommendations. If you have bad recycled battery you cant expect some good performance and capacity and during charging maybe some bad things will happen, as higher temperature, battery body expanding, ....

I prefer C/10 rule. 1000mAh 100mA for smaller batteries, and for higher around 4000mAh 400mA. I'm rather to make safer charger then faster. I have several times few 18650 4Ah cells which die hard, and they overheating during charging process, because I have separate and individual cell charging I notice that and remove thise bad cells. I cant imagine what will happen if charger is for C1 or higher and left alone unattended.

There is lots of various charging circuits and branded chargers which charge branded batteries up to C15, 15 times of battery capacity or chargers called "minute charger".

:wink:

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For your battery 500mAh I will use max 100mAh. Of course this is my thinking, you can choose different charging rate. You can make charger with selectable resistor to define charging rate for IC. With that you can have many charging rate options, according to situations and place where you using device. Make few cycling tests with different charging rates and monitor what happening with battery, watch temperature stick good temp sensor on battery body and log on each sec value, also measure with Nonius external measures of battery body, and compare dimensions before and after (dimensions for your type and shape of battery).