Electronic Components Datasheet Search |
|
IS32LT3174 Datasheet(PDF) 10 Page - Integrated Silicon Solution, Inc |
|
IS32LT3174 Datasheet(HTML) 10 Page - Integrated Silicon Solution, Inc |
10 / 16 page IS32LT3174 Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 06/14/2016 10 APPLICATION INFORMATION The IS32LT3174 is a single channel linear current driver optimized to drive an automotive interior map light, or other interior lamp which is frequently toggled between the on and off condition. The device integrates an input control for the channel allowing for on/off operation. In addition, a programmable fade in and fade out feature is integrated into channel’s control block to allow the end customer maximum flexibility in setting up their light timing requirements. The regulated LED current (up to 200mA) is set by a single reference resistor (RISET). OUTPUT CURRENT SETTING A single programming resistor (RISET) controls the maximum output current for output channel simultaneously. The programming resistor may be computed using the following Equation (1): SET ISET I R 2000 (1) (10kΩ≤RISET≤100kΩ) The device is protected from an output overcurrent condition caused by an accidental short circuit of the ISET pin, by internally limiting the maximum current in the event of an ISET short circuit to 260mA. EN PIN OPERATION The EN inputs to the device include internal pull-up sources so that no external components are required to provide the input high level to the pin. The output channel powers up in the ‘OFF’ condition. Toggling the EN pin from high to low on a given channel for a period of time that exceeds the debounce time will cause that channel’s output to toggle from the OFF condition to the source condition. When this happens, the output current of the channel gradually ramps up from zero to the programmed value (set by RISET) over the time set by the resistor (RTSET) attached to the ISET pin. Conversely, if a channel is already in the source condition, and that channel’s EN pin is toggled low, then the output current shall begin to ramp down towards zero in the time period as programmed by the resistor (RTSET) attached to the TSET pin. Note, the EN input is available during the period of either fade in or fade out condition. Figure 18 EN Debounced Debounce - Output control is provided by a debounced switch input, providing an ON/OFF toggle action for various switch or button characteristics. An internal debounce circuit will condition the input signal so a single press of the mechanical switch doesn't appear like multiple presses. The EN input is debounced by typically 37ms. Note: The debounce time applies to both falling and rising edges of the EN signal. FADE IN AND FADE OUT When an EN channel is turned on (pulled low), the output current of the channel shall gradually ramp up from zero to the final value as programmed by the resistor (RISET) connected to the ISET pin. The time period over which the ramping happens is determined by the resistor (RTSET) connected to the TSET pin. The output current shall ramp up (or down) in 63 steps, with integrated gamma correction for an extremely linear ramping of the luminous output of the LED bulb. SETTING THE FADE TIME The fade time, either in or out, for channel is set by a single external programming resistor (RTSET). The fade time is programmable by Equation (2): s R t TSET 5 . 2 (2) For example, RTSET=100kΩ, fade time is about 0.25s. Note: In order to get the optimized effect, the recommended fading time is between 1.5s (RTSET=600kΩ) and 0.25s (RTSET=100kΩ). If the TSET pin is tied directly to GND, the fade in/out function is canceled and the ramp time is about 73µs, or ‘instant on’. However, the debounce feature of the EN pin is not disabled. |
Similar Part No. - IS32LT3174 |
|
Similar Description - IS32LT3174 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |