LED Driver ICs Forum Discussions

TLD5099EP  can be used with 3.3 V and 5 V microcontrollers without any problems. The EN/PWMI pin thresholds are designed to be compliant with both uC standards. 

For more information please visit our LITIX Power webpage and the TLD5099EP webpage.

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OUT_SET pin mirrors the IIN_SET current set by the external resistor RSET. Any change on the IIN_SET current will be mirrored to the OUT_SET pin.

PWM may be applied in two different ways in an application.

PWM via PWMI-pin
When PWM is applied via PWM-pin of the first IC only, this will not be propagated to the second and subsequent ICs. Reason is that the IN_SET current is not affected by the PWMI-pin status and will remain stable during the deactivation phase of the PWM. Therefore, the second IC channels will be constantly active while the first IC channel will operate in PWM.
In this case, we have to apply the same PWM to the PWMI-pin of all the ICs in the application.

PWM via IN_SET-pin
When PWM is applied via IN_SET pin of the first IC only, this will be propagated to the second and subsequent ICs. IN_SET current will change according to the PWM and those changes will be mirrored to the OUT_SET pin and therefore will be propagated to the second IC.

IN_SET to OUT_SET activation and deactivation delay times have to be considered for a synchronized result (P_6.6.10, P_6.6.11).


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SEPIC DC-DC converter needs two inductors to properly work. The two inductors can be wrapped on the same core (coupled inductors) or on two separated cores (uncoupled inductors).

SEPIC using coupled inductors shows

• higher efficiency due to reduced magnetic core losses
  
• reduces PCB area because it needs the space for only one magnetic component
  
• simpler compensation due to simple transfer function
  

On the other hand SEPIC using uncoupled inductors can benefit of components coming from a wider inductance selection thus proving flexibility in the system design.

To see how to use LITIX Power DC-DC controller in SEPIC topology, please have a look at the LITIX Power webpage Show Less

With LITIX Power boost controllers it is possible to implement a delay and fade-in / fade-out functions without using a microcontroller.

This can be done by using filters with different time constant at the SET pin. The SET pin is the analog adjustment input and it is used to control the output current. One of the filters needs to be switchable.

In the example below

Filter 1 is a low pass filter that enables and disables the output current with a defined delay by closing or opening the MOSFET
Filter 2 is a low pass filter that enables the fade-in/fade-out function.



For further details you can also visit LITIX Power webpage Show Less

ERRN status remains low when the fault is present on the output even during the IN_SET de-activation time (IN_SET open via uC).
This happens because ERRN status depends only on the OUTx and EN/DEN voltages. It doesn't depend on any change of resistive load at IN_SET.
When a fault (OL/SC) occurs the IN_SET regulation turns off: VIN_SET goes to GND after tfault and D charge phase.
Open load:


Short circuit:


For more information on the LITIX™ Basic+ diagnostics check the product datasheet and the application note "Litix™ Basic+ LED driver family: Diagnosis and fault management" Show Less

GNDS-pin must be connected to GND and can't be left open.

For more information check the LITIX™ Basic webpage. Show Less

The pull-up resistor at ST-pin is calculated according to following equation:
RST > VREG/IST, where VREG is the pull-up voltage for the ST-pin (see IST in datasheet):




See following example:

• ST is pulled-up to 5V
  
• RST > 5V/IPD = 5V/1.5mA = 3.3kOhm. Considering tolerances a RST > 4.5kΩ is recommended.
  

For more information check the LITIX™ Linear TLE4242G webpage. Show Less

The minimum current of LITIX™ Basic+ is limited by the IN_SET output activation current, IIN_SET(ACT) (data sheet parameter P_6.2.2): IOUTmin = IIN_SET(ACT) * k

1-channel ICs (TLD2132-1EP, TLD2142-1EP): IOUTmin = IIN_SET(ACT) * k = 15uA * 900 = 13.5 mA

3-channel ICs (TLD2131-3EP, TLD2331-3EP, TLD2141-3EP): IOUTmin = IIN_SET(ACT) * k = 15uA * 300 = 4.5 mA

2-channel IC (TLD2252-2EP): Channel 1 IOUTmin = IIN_SET(ACT) * k = 15uA * 300 = 4.5 mA, Channel 2 IOUTmin = IIN_SET(ACT) * k = 15uA * 600 = 9 mA

Note: For TLD2132-1EP, TLD2131-3EP and TLD2331-3EP, the Single LED Short detection needs to be taken into consideration. The minimum specified IN_SET current of KSLS_REF is 50uA (data sheet parameter P_7.5.13). This means that for applications where SLS detection is required, the output current is IOUT = 50uA * 300 = 15 mA. In case SLS detection is not required, the minimum output current depends on the IIN_SET(ACT) only and is IOUT = 4.5 mA

Note: For applications where a lower output current is required, it is possible to use PWM signal in order to achieve a significantly lower average output current, IOUT. For example, one can set the IOUT at 30mA (via RSET) and with use of PWM with duty cycle of 7% to achieve a lower average output current IOUT=2mA Show Less

The TLD509x mainly differ in maximum output voltage, output current accuracy, analog dimming, short-to-ground protection and capability to drive an external NMOS for dimming purpose from each other:

Maximum output voltage:

TLD5095: 45 V

TLD5097: 61 V

TLD5098: 61 V

TLD5099EP: 61 V

LED current accuracy:

TLD5095: 5%

TLD5097: 3%

TLD5098: 3%

TLD5099EP: 3%

analog dimming:

TLD5095: No

TLD5097: Yes

TLD5098: Yes

TLD5099EP: Yes

Output short-circuit protection:

TLD5095: No

TLD5097: No

TLD5098: Yes

TLD5099EP: Yes

Digital PWM dimming:

TLD5095: Yes, with dedicated PWM gate driver

TLD5097: Yes

TLD5098: Yes, with dedicated PWM gate driver

TLD5099EP: Yes, with dedicated PWM gate driver

Embedded PWM engine:

TLD5095: No

TLD5097: No

TLD5098: No

TLD5099EP: Yes, 8 bit resolution; frequency adjustable with external capacitor

Spread spectrum:

TLD5095: No

TLD5097: No

TLD5098: No

TLD5099EP: Yes, 7KHz modulation frequency

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A thermal protection circuitry is integrated in the LITIX™ Basic+ devices. It is realized by a temperature monitoring of the output stages.
The reaction is different for the TLD2x3x-xEP /TLD214x-xEP and the TLD2252-2EP /TLD1114-1EP devices:

TLD2x3x-xEP, TLD214x-xEP
As soon as the junction temperature exceeds the current reduction threshold _T_j(CRT) = 140°C [P_6.5.44], the device reduces the IN_SETx reference voltage, VIN_SETx(ref) [P_6.6.1]. Since the IN_SET current is function of the IN_SET reference voltage, it decreases as well according to IIN_SETx(ref) = VIN_SETx(ref)/RSETx.
If the device temperature still increases, the output current decreases close to 0 A. As soon as the device cools down the output current rises again.
Note: the thermal foldback works only when the IN_SET is connected to a resistor and not to a regulated current sink.


TLD2252-2EP, TLD1114-1EP
As soon as the junction temperature exceeds the overtemperature threshold TJSD = 175°C (typ) [P_6.5.42], the output is disabled and the IN_SET pin goes in a weak pull-down state with a current consumption IIN_SET(fault) = 10 uA [P_7.5.1].
If the temperature cools down below TJSD - TJ(hys) = 175°C - 10°C [P_6.5.43], the IN_SET rises again to VIN_SET(ref) [P_6.6.1] within an additional time tIN_SET(del) [P_7.5.4]. Consequently, the output current rises again.

The overtemperature condition is reported to the ERRN pin and can be used to deactivate other LITIX™ Basic+ devices connected to the same ERRN network.


For more information check the LITIX™ Basic+ webpage. Show Less