MIKROE-2807

MIKROE-2807 Datasheet

PID MIKROE-2807

Part	Datasheet
MIKROE-2807	MIKROE-2807 (pdf)

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LED driver 2 click PID MIKROE-2807 Weight 25 g LED driver 2 click carries the MCP1643 - LED constant current regulator, made by Microchip. It is a compact, high-efficiency, fixed frequency, synchronous step-up converter, optimized to drive one LED with the constant current. It can be powered by a two-cell alkaline/NiMH/NiCd battery 2.4V , or via the mikroBUS power supply pins. LED Driver 2 click also features 3W High brightness LED by QT-Brightek. This LED can be dimmed by applying the variable duty cycle PWM signal to the EN pin of the MCP1643 regulator, through the PWM pin of the mikroBUS . Thanks to its relatively high constant current driving capability and the overvoltage protection on the output, this integrated circuit is perfectly suited for high brightness/power LED applications portable LED lighting products, LED Flashlight and Head Lamps, Rechargeable Flashlights, General LED constant current applications and so on. How does it work? MCP1643 is basically a boost regulator with a low voltage reference of 120mV VFB . The main feature of the regulator is that it is optimized to keep the current running through the LED constant, by regulating the voltage across the feedback resistor. The VFB pin is used to regulate the voltage across the feedback resistor to 120 mV, keeping the output LED current regulated. As feedback resistor R2 on the provided schematic is connected to the FB pin and its resistance is the maximum current through the LED can easily be calculated by using the following formula ILED = VFB/R2 = = 300mA. The voltage drop on the feedback resistor has to be low, in order to avoid dissipation. In the case of MCP1643, this voltage is set to 120mV which ensures no dissipation issues at all. The onboard VIN SEL SMD jumper offers the selection of the input voltage source it can be set to use a two-cell NiMH battery connected to VIN terminal 2.4V , or the power supply pin from the mikroBUS . The voltage from the mikroBUS can be set with the VCCIO SMD jumper to either 5V or 3.3V. Since the forward voltage on the high power LED is 3.2V, the click board comes equipped with the MCP1826, an LDO regulator by Microchip, which is used to drop the selected mikroBUS voltage down to around 2.4V so that the MPC1643 input voltage requirements are met. High brightness 3W LED is already attached to the output of the MCP1643 and it comes soldered on the board, so the circuit is ready to be used right away. The LED brightness can be regulated by applying a variable duty cycle PWM signal to the EN pin of the MCP1643 regulator routed to PWM pin on the mikroBUS . This results in changing the current running through the LED in a linear fashion, from 0 to the value set by the resistor, depending on the PWM cycle. The device also features an output overvoltage protection that limits the output voltage to 5.0V typical, in case the LED fails or output load is disconnected. Also, the device features a thermal shutdown at +150°C with a hysteresis of +25°C and the overcurrent protection that prevents failures due to short circuits on the output. Specifications Type Boost modules Microchip’s MCP1643 1MHz low voltage synchronous boost LED constant current regulator Key Features Overvoltage protection, true load disconnect, dimming control by variable duty cycle, overtemperature protection Interface Input Voltage 3.3V or 5V Click board size L x mm Pinout diagram This table shows how the pinout on LED driver 2 click corresponds to the pinout on the mikroBUS socket the latter shown in the two middle columns . Notes Notes AN PWM 16 MISO SCL MOSI SDA Power supply 3V3 7 3.3V Ground GND 8 PWM NC 5V GND MCP1643 Enable Power supply Ground LED driver 2 click electrical specifications Min Typ Max Unit Battery supply voltage High Brightness LED current 0 Onboard settings and indicators

PDF Datasheet Preview

LED driver 2 click

PID MIKROE-2807

Weight 25 g

LED driver 2 click carries the MCP1643 - LED constant current regulator, made by Microchip. It is a compact, high-efficiency, fixed frequency, synchronous step-up converter, optimized to drive one LED with the constant current. It can be powered by a two-cell alkaline/NiMH/NiCd battery 2.4V , or via the mikroBUS power supply pins. LED Driver 2 click also features 3W High brightness LED by QT-Brightek. This LED can be dimmed by applying the variable duty cycle PWM signal to the EN pin of the MCP1643 regulator, through the PWM pin of the mikroBUS .

Thanks to its relatively high constant current driving capability and the overvoltage protection on the output, this integrated circuit is perfectly suited for high brightness/power LED applications portable LED lighting products, LED Flashlight and Head Lamps, Rechargeable Flashlights, General LED constant current applications and so on.

How does it work?

MCP1643 is basically a boost regulator with a low voltage reference of 120mV VFB . The main feature of the regulator is that it is optimized to keep the current running through the LED constant, by regulating the voltage across the feedback resistor. The VFB pin is used to regulate the voltage across the feedback resistor to 120 mV, keeping the output LED current regulated. As feedback resistor R2 on the provided schematic is connected to the FB pin and its resistance is the maximum current through the LED can easily be calculated by using the following formula ILED = VFB/R2 = = 300mA.

The voltage drop on the feedback resistor has to be low, in order to avoid dissipation. In the case of MCP1643, this voltage is set to 120mV which ensures no dissipation issues at all.

The onboard VIN SEL SMD jumper offers the selection of the input voltage source it can be set to use a two-cell NiMH battery connected to VIN terminal 2.4V , or the power supply pin from the mikroBUS . The voltage from the mikroBUS can be set with the VCCIO SMD jumper to either 5V or 3.3V. Since the forward voltage on the high power LED is 3.2V, the click board comes equipped with the MCP1826, an LDO regulator by Microchip, which is used to drop the selected mikroBUS voltage down to around 2.4V so that the MPC1643 input voltage requirements are met.

High brightness 3W LED is already attached to the output of the MCP1643 and it comes soldered on the board, so the circuit is ready to be used right away.

The LED brightness can be regulated by applying a variable duty cycle PWM signal to the EN pin of the MCP1643 regulator routed to PWM pin on the mikroBUS . This results in changing the current running through the LED in a linear fashion, from 0 to the value set by the resistor, depending on the PWM cycle.

The device also features an output overvoltage protection that limits the output voltage to 5.0V typical, in case the LED fails or output load is disconnected. Also, the device features a thermal shutdown at +150°C with a hysteresis of +25°C and the overcurrent protection that prevents failures due to short circuits on the output.

Specifications

Type

Boost
modules

Microchip’s MCP1643 1MHz low voltage synchronous boost LED constant current regulator

Key Features Overvoltage protection, true load disconnect, dimming control by variable duty cycle, overtemperature protection

Interface

Input Voltage 3.3V or 5V

Click board size L x mm

Pinout diagram

This table shows how the pinout on LED driver 2 click corresponds to the pinout on the mikroBUS socket the latter shown in the two middle columns .

Notes

Notes

AN PWM 16

MISO SCL

MOSI SDA

Power supply 3V3 7
3.3V

Ground

GND 8

PWM NC 5V GND

MCP1643 Enable

Power supply Ground

LED driver 2 click electrical specifications

Min Typ Max

Unit

Battery supply voltage

High Brightness LED current 0

Onboard settings and indicators

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived MIKROE-2807 Datasheet file may be downloaded here without warranties.

Datasheet ID: MIKROE-2807 649439