PCA9532 16-bit I C LED dimmer - E-LAB Computers

More documents

Recommendations

Info

Philips SemiconductorsProduct data16-bit I 2 C LED dimmerPCA9532APPLICATION DATA5 V5 VSDASDAV DDLED0LED1LED2SCLSCLLED3RESETLED4LED5LED6LED7LED8I 2 C/SMBus MASTERA2A1A0LED9LED10LED11LED12V SSLED13LED14GPIOsLED15PCA9532Note: LED0 to LED12 are used as LED driversLED13 to LED15 are used as regular GPIOs.SW02044Figure 13. Typical applicationMinimizing I DD when the I/O is used to control LEDsWhen the I/Os are used to control LEDs, they are normally connected to V DD through a resistor as shown in Figure 13. Since the LED acts as adiode, when the LED is off the I/O V IN is about 1.2 V less than V DD . The supply current, I DD , increases as V IN becomes lower than V DD and isspecified as ∆I DD in the DC characteristics table.Designs needing to minimize current consumption, such as battery power applications, should consider maintaining the I/O pins greater than orequal to V DD when the LED is off. Figure 14 shows a high value resistor in parallel with the LED. Figure 15 shows V DD less than the LED supplyvoltage by at least 1.2 V. Both of these methods maintain the I/O V IN at or above V DD and prevents additional supply current consumption whenthe LED is off.V DD3.3 V5 VLED100 kΩV DDV DDLEDLEDxLEDxSW02086Figure 14. High value resistor in parallel with the LEDFigure 15. Device supplied by a lower voltageSW020872003 May 02 10
Philips Semiconductors16-bit I 2 C LED dimmerProduct dataPCA9532Programming exampleThe following example will show how to set LED0 to LED3 on. It willthen set LED4 and LED5 to blink at 1 Hz at a 50% duty cycle. LED6and LED7 will be set to be dimmed at 25% of their brightness (dutycycle = 25%). LED8 to LED15 will be set to off.Table 1.StartPCA9532 address with A0-A2 = LOWPSC0 subaddress + auto-incrementSet prescaler PSC0 to achieve a period of 1 second:Blink period 1 PSC0 1152PSC0 = 151Set PWM0 duty cycle to 50%:PWM0256 0.5PWM0 = 128Set prescaler PCS1 to dim at maximum frequencyI 2 C-busSC0h12h97h80h00hBlink period maximumPSC1 = 0Set PWM1 output duty cycle to 25%:PWM1256 0.25PWM1 = 64Set LED0 to LED3 onSet LED4 and 5 to PWM0, and LED6 or 7 to PWM1Set LED8 to LED11 offSet LED12 to LED15 offStop40h55hFAh00h00hP2003 May 02 11
Page 1 and 2: INTEGRATED CIRCUITSPCA953216-bit I
Page 3 and 4: Philips Semiconductors16-bit I 2 C
Page 9: Philips Semiconductors16-bit I 2 C
Page 19 and 20: Philips SemiconductorsProduct data1

PCA9532 16-bit I C LED dimmer - E-LAB Computers

Create successful ePaper yourself

Delete template?

Save as template?