Freescale Semiconductor S08 manual LED Driving Board

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Hardware Description

Table 2-13. User Assignable Input (Continued)

CON13	Signal Name	Remarks

Pin 7	DCDC_CTL1	Connected to MCU PTF4/TPM2CH0

Pin 8	DCDC_CTL2	Connected to MCU PTF5/TPM2CH1

Pin 9	DCDC_CTL3	Connected to MCU PTE3/TPM1CH1

Pin 10	GND	—

2.10 LED Driving Board

In general, LEDs have a nonlinear I-V behavior and current limitation is required to prevent the power dissipation to exceed a maximum limit. Therefore, the ideal source for LED driving is a constant current source. A linear type LED driver is used in this reference design and the block diagram is shown in Figure 2-4. The major advantage of linear driver is fast turn ON and OFF response times to support high frequency PWM dimming method and wide range control on dimming level. An integrated DC-to-DC boost converter (MC34063) generates the high voltage required for LED driving in series and is shared with RGB channels, but the drawback is the power loss on R channel is higher than G or B channels. Individual DC-to-DC block should be used for each channel in power sensitive applications.

LED Lighting Control using the MC9S08AW60, Rev. 1

18	Freescale Semiconductor

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Contents LED Lighting Control Using the MC9S08AW60 Page LED Lighting Control using the MC9S08AW60 Revision HistoryDesigner Reference Manual Freescale Semiconductor Table of Contents Appendix a Schematics Appendix B Bill of Materials Features Chapter IntroductionIntroduction System Overview MC9S08AW60Devices in the MC9S08AW60/48/32/16 Series Peripherals Available per Package Type Introduction LED Lighting Control using the MC9S08AW60, Rev Chapter Hardware Description AW60 Control BoardDEMO9S08AW60LED Features DEMO9S08AW60LED LayoutDevelopment Support PowerReset Switch Clock SourceUser Options Pushbutton SwitchesLED Indicators ADC InterfaceSCI Port Other I/O ConnectorsIIC Port SPI PortPWM Port LED Light Box Interface10. Sensor Interface Type a 12. Temperature Sensor Input 11. Sensor Interface Type H13. User Assignable Input LED Driving Board LED Driver Design Procedures RGB LED ChipCurrent Sense Resistor Boost ConverterEquations for Boost Converter Freescale Semiconductor Chapter Firmware Description Firmware Flow Main ProgramPC Control Mode Firmware Flow PWM AdjustmentUser Interface Menu Standalone Mode Firmware Files Freescale Semiconductor Hardware Setup Chapter Demo SetupHardware and Software Setup PC Software SetupEcho Typed Characters Setting Demo Examples Demo 1 Demonstration DisplayDemo 4 PWM Output Frequency Control Demo 2 Preset Colors DisplayDemo 3 Auto White Balance Control Demo 5 Full Manual ControlTroubleshooting Program the MCU FlashDemo Setup Appendix a Schematics LED Lighting Control using the MC9S08AW60, Rev LED Lighting Control using the MC9S08AW60, Rev LED Lighting Control using the MC9S08AW60, Rev LED Lighting Control using the MC9S08AW60, Rev LED Lighting Control using the MC9S08AW60, Rev Appendix B Bill of Materials BOM for AW60 Control Board Part Description Quantity Value DesignatorsBOM for LED Driving Board Value DesignatorsLED Lighting Control using the MC9S08AW60, Rev Page How to Reach Us