HT46R47 D/NHA0163E LM7805 - Datasheet Archive

 

7-inch WLED Backlight Display Application for the HT46R47 D/NHA0163E Introduction The HT46R47 8-bit MCU can be used to illuminate

 

7-inch WLED Backlight Display Application for the HT46R47 HT46R47 7-inch WLED Backlight Display Application for the HT46R47 HT46R47 D/NHA0163E D/NHA0163E Introduction The HT46R47 HT46R47 8-bit MCU can be used to illuminate a 7-inch WLED backlight LCD display and be used to control the brightness. Features Operating Voltage: fSYS=4MHz: 2.2V~5.5V fSYS=8MHz: 3.3V~5.5V 13 to 23 bidirectional I/O lines One external interrupt input shared with an I/O line 8-bt programmable timer/event counter with overflow interrupt and 7 stage prescaler On-chip crystal and RC oscillator Watchdog Timer PFD for sound generation HALT and wake-up function reduce power consumption Up to 0.5s instruction cycle with 8MHz system clock at VDD=5V 4 or 6-level subroutine nesting 4 channel 8 or 9-bit resolution A/D converter 1 or 2 channels 8-bit PWM output shared with an I/O line Bit manipulation instruction Table read instructions 63 power instructions All instructions in one or two machine cycles Low voltage reset function Many package types 1 7-inch WLED Backlight Display Application for the HT46R47 HT46R47 Hardware Diagram Hardware Diagram Hardware Diagram Description Power: a 12V input voltage supplies the backlight board and at the same time supplies the MCU with 5V through a 7805 regulator. Power Control: amplify the MCU output PWM waveform to drive the backlight board by controlling the average current. Current Detect: detect if the current has reached the target value and adjust the PWM output to the correct value. Control Button: set the mark to space ratio of the PWM output to control the brightness of the backlight board with five levels in all. 2 7-inch WLED Backlight Display Application for the HT46R47 HT46R47 Hardware Circuit Description Overall Circuits Hardware Circuit Function Description The 12V power input voltage, also generates a 5V voltage through an LM7805 LM7805, are respectively provided as the charger and MCU operating voltages. The HT46R47 HT46R47 uses an external RC oscillator. PB0/AN0 is used to measure the current and the PWM controls the current output. Use the "UP" and "DOWN" keys to adjust the PWM to control the LED brightness by changing the current. The power circuit provides the power drive circuit and the 15 and 5V voltage for the MCU circuit. 3 7-inch WLED Backlight Display Application for the HT46R47 HT46R47 Software Design Description Main Flowchart Software Flow Description Initialize all I/O lines Send a PWM of a fixed width, read the voltage converted from the current through the A/D and adjust the corresponding PWM value according to the voltage value. If the detected voltage value is small, it indicates no overloading and that no other problem exists and the PWM output can be disabled as well as setting it to zero to wait for a Reset. If the voltage value is too big, to protect the LED board, disable the PWM output in the same way and set the PWM to zero to wait for a Reset. There are two control buttons, one for brightness control and the other for dimness control that are implemented by setting target value for the A/D conversion. If it is a RESET or Power-on, the brightness current will be maintained within a range of 44~220mA. 4 7-inch WLED Backlight Display Application for the HT46R47 HT46R47 PCB Layout TOP Layer 5