zxld1350 Zetex Semiconductors plc., zxld1350 Datasheet
zxld1350
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zxld1350 Summary of contents
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... Depending upon supply voltage and external components, this can provide watts of output power. The ZXLD1350 includes the output switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current. ...
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... ADJ pin grounded ADJ pin floating f=250kHz Measured on I SENSE respect =1.25V ADJ V =V -0.1 SENSE IN Measured on ADJ pin with pin floating REF (†) V falling ADJ V rising ADJ 2 ZXLD1350 Min. Typ. Max 4 250 500 95 100 105 pin with ±15 1.25 10 1.21 1.25 1.29 50 0.3 2.5 0.15 0.2 ...
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... S <2.5V) to adjust output current from 25% to 200% ADJ for f>10kHz and 1% to 100 OUTnom from this pin define nominal average output current with ADJ pin open-circuit) Reel width (mm ZXLD1350 Min. Typ. Max. 0.01 1 100:1 0.16 1 5:1 500 =3.4V 250 200 200 1 0 ...
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... Block diagram V IN Voltage regulator C1 ADJ Vref GND Issue 6 - April 2007 © Zetex Semiconductors plc 2007 Shutdown circuit R2 4KHz 200k 1.25V R3 4 ZXLD1350 SENSE Current sense circuit - + Comparator - + www.zetex.com ...
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... L1 and the LED(s). The current rises at a rate determined across R . The supply referred voltage V SENSE S pin with respect The average output current ZXLD1350 ), forms a self-oscillating S is zero and there the comparator output switches ADJ . The current IN , the comparator output switches ADJ ...
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... LX voltage SENSE voltage Coil current 0V Comparator V input voltage ADJ 5V Comparator output 0V Issue 6 - April 2007 © Zetex Semiconductors plc 2007 Toff Ton 115mV 85mV 0.15V ADJ Figure 1 Operating waveforms 6 ZXLD1350 100mV V SENSE- V SENSE+ I +15% OUTnom I OUTnom I -15% OUTnom 0.15V ADJ www.zetex.com ...
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... Typical operating waveforms [V Normal operation. Output current (Ch3) and LX voltage (Ch1) Start-up waveforms. Output current (Ch3), LX voltage (Ch1) and VADJ (Ch2) Issue 6 - April 2007 © Zetex Semiconductors plc 2007 =12V, R =0.3 , L=100µ ZXLD1350 www.zetex.com ...
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... ZXLD1350 =12V and T =25°C unless IN amb ...
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... ZXLD1350 Vref vs Vin at low supply voltage Vin ( ...
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... ZXLD1350 ...
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... Zetex Semiconductors plc 2007 and I IN SENSE if the ADJ pin is driven from an external voltage. (See shown, to adjust the output current ADJ <2.5V] ADJ = V ADJ REF exceeding 370mA maximum. OUTdc ±25%. 13 ZXLD1350 S and is given by: (=1.25V). REF . S . When driving the ADJ pin above www.zetex.com ...
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... See the section on PWM dimming for more details of the various modes of control using high frequency and low frequency PWM signals. Issue 6 - April 2007 © Zetex Semiconductors plc 2007 ZXLD1350 GND ZXLD1350 GND ZXLD1350 GND 14 ZXLD1350 can be applied to the ADJ pin, as PWM www.zetex.com ...
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... NOT be used. A table of recommended manufacturers is provided below: Manufacturer Website Murata www.murata.com Taiyo Yuden www.t-yuden.com Kemet www.kemet.com AVX www.avxcorp.com Issue 6 - April 2007 © Zetex Semiconductors plc 2007 ZXLD1350 will increase REF www.zetex.com ...
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... Inductor selection Recommended inductor values for the ZXLD1350 are in the range 220 H. Higher values of inductance are recommended at higher supply voltages in order to minimize errors due to switching delays, which result in increased ripple and lower efficiency. Higher values of inductance also result in a smaller change in output current over the supply voltage range ...
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... This gives an operating frequency of 546kHz and a duty cycle of 0.34. These and other equations are available as a spreadsheet calculator from the Zetex website www.zetex.com/zxld1350 Note that in practice, the duty cycle and operating frequency will deviate from the calculated values due to dynamic switching delays, switch rise/fall times and losses in the external components ...
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... Issue 6 - April 2007 © Zetex Semiconductors plc 2007 Cled ZXLD1350 led 2 PCB www.zetex.com ...
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... The LEDs are usually mounted remotely from the device, so for this reason, the temperature coefficients of the internal circuits for the ZXLD1350 have been optimized to minimize the change in output current when no compensation is employed. If output current compensation is required possible to use an external temperature sensing network - normally using Negative Temperature Coefficient (NTC) thermistors and/or diodes, mounted very close to the LED(s) ...
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... Evaluation PCB The picture below shows the top copper layout of the 3 LED ZXLD1350EV2 evaluation board. This board and other evaluation boards for the ZXLD1350 are available upon request. ZXLD1350EV2 k EVALUATION BOARD D1 a JP1 JP2 +VIN SD1 GND R1 JP3 ...
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... To minimize this error, the PWM duty cycle should be as low as possible consistent with avoiding flicker in the LED. Issue 6 - April 2007 © Zetex Semiconductors plc 2007 proportional to the PWM duty cycle. OUTavg Ton Toff >0 01] 21 ZXLD1350 200mV 0.1/Rs IOUTavg www.zetex.com ...
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... This mode will give minimum output ripple and reduced radiated emission, but with a reduced dimming range (approx.5:1). The restricted dimming range is a result of the device being turned off when the dc component on the filter output falls below 200mV. Issue 6 - April 2007 © Zetex Semiconductors plc 2007 Ton >0.16] PWM 22 ZXLD1350 Toff www.zetex.com I OUTnom ...
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... Issue 6 - April 2007 © Zetex Semiconductors plc 2007 Millimeters Max. - 1.00 0.10 0.90 0.45 0.20 2.90 BSC 2.80 BSC 1.60 BSC 0.95 BSC 1.90 BSC 0.50 0.25 BSC 12° 23 ZXLD1350 Inches Min. Max. - 0.0393 0.0003 0.0039 0.0330 0.0354 0.0118 0.0177 0.0047 0.0078 0.114 BSC 0.110 BSC 0.062 BSC 0.0374 BSC 0.0748 BSC 0.0118 ...
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... Zetex Semiconductors plc 3701-04 Metroplaza Tower 1 Zetex Technology Park, Chadderton Hing Fong Road, Kwai Fong Oldham, OL9 9LL Hong Kong United Kingdom Telephone: (852) 26100 611 Telephone: (44) 161 622 4444 Fax: (852) 24250 494 Fax: (44) 161 622 4446 asia.sales@zetex.com hq@zetex.com 24 ZXLD1350 www.zetex.com ...