BD93941EFV Datasheet, PDF (9/30 Pages) Rohm – LED pin rating 60V

BD93941EFV BD93941FP
Datasheet
Pin Function
○AUTO (1pin)
This sets up time till auto-restart time from the point of abnormal detection. Having 1μA constant current charge at external
capacitor connected to AUTO pin, it will start again when it becomes over 4.0V (The auto pin is shorted to GND, this IC’s
protection function operates latched off mode).
○Auto-restart period vs. AUTO capacitance (Ideal)
T _AUTO
 ^{4.0[V ]  C AUTO}
1.0  10 ^6 [ A]
 4.0  10 ⁶  C _AUTO [sec]
○REG58 (2pin)
The REG58 pin is used in the DC/DC converter driver block to output 5.8V power. The maximum operating current is 15mA.
Using the REG58 pin at a current higher than 15mA can affect the N pin output pulse, causing the IC to malfunction and
leading to heat generation of the IC itself. To avoid this problem, it is recommended to make load setting to the minimum
level.
Please place the ceramic capacitor connected to REG58 pin (2.2μF～10μF) closest to REG58-GND pin.
○CS (3pin)
The CS pin has the following two functions:
1. DC/DC current mode current feedback function
Current flowing through the inductor is converted into voltage by the current sensing resistor RCS connected to the CS pin
and this voltage is compared with voltage set with the error amplifier to control the DC/DC output voltage.
2. Inductor current limit function
The CS pin also incorporates the over current protection (OCP) function. If the CS pin voltage reaches 0.45V (Typ.) or more,
switching operation will be forcedly stopped.
○N (4pin)
The N pin is used to output power to the external NMOS gate driver for the DC/DC converter in the amplitude range of
approx. 0 to REG58. ON resistances is 4.0Ω(typ.) in sorrce (H side), 3.0Ω(typ.) in sink (L side).
Frequency setting can be made with a resistor connected to the RT pin. For details of frequency setting, refer to the
description of the RT pin.
○DCDC_GND (5pin)
The PGND pin is a power ground pin for the driver block of the output pin N.
○OVP (6pin)
The OVP pin is an input pin for over-voltage protection and short circuit protection of DC/DC output voltage. If over-voltage
is detected, the OVP pin will stop the DC/DC converter conducting step-up operation. When the short circuit protection
(SCP) function is activated, the DC/DC converter will stop operation, and then the timer will start counting. When the timer
completes counting the preset period of time, the LED drivers are stopped.
The OVP pin is of the high impedance type and involves no pull-down resistor, resulting in unstable potential in the
open-circuited state. To avoid this problem, be sure to make input voltage setting with the use of a resistive divider or
otherwise.
○STB (7pin)
The STB pin is used to make setting of turning ON and OFF the IC and allowed for use to reset the IC from shutdown.
Note: The IC state is switched (i.e., the IC is switched between ON and OFF state) according to voltages input in the STB
pin. Avoid using the STB pin between two states (0.8 to 2.0V).
○LED1 – LED4 (8,9,11,12pin)
The LED1 to 4 pins are used to output constant current to LED drivers. Current value setting can be made by connecting a
resistor to the ISET pin. For the current value setting procedure, refer to the description of “ISET pin”.
If any of the LED pins is put in an erroneous state (e.g. short circuit mode, open circuit mode, or ground short circuit mode),
the relevant protection function will be activated.
○LED_GND (10pin)
The LED_GND pin is a power ground pin used for the LED driver block.
○PWM (13pin)
The PWM pin is used to turn ON and OFF LED drivers. Light can be modulated by changing the duty cycle through the
direct input of a PWM light modulation signal. The high and low voltage levels of PWM pin is as listed in the table below:
State
LED ON state
LED OFF state
PWM Voltage
PWM= 2.0V to 35V
PWM= -0.3V to 0.8V
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TSZ22111・15・001
9/27
TSZ02201-0F1F0C100270-1-2
10.Oct.2013 Rev.001