![]() |
Electronic Components Datasheet Search |
|
TPS61160DRVTG4 Datasheet(PDF) 23 Page - Texas Instruments |
|
|
|
TPS61160DRVTG4 Datasheet(HTML) 23 Page - Texas Instruments |
23 / 39 page ![]() FLTR pwm FLTR 1 1 C = 2 (R // R ) 10 f p 2 L ED(ma x) PW M(max) FB LED(min) PW M(min) FB PWM(max) PWM(min) 1 FLTR FB LED(max) LED(min) LE D(max) LED(min) R (I (V V ) I (V V )) V V R + R = + V (I I ) I I - - - - - - ( ) FB PWM(max) PWM(min) SET P WM(ma x) LE D(max) FB LED(max) FB L ED(min ) PWM(min) L ED(min ) V V V R = V I V I + V I V I - - P WM(ma x) (ma x) PWM(H) (max) PWM(L) V = D V + (1 D )V - PWM(min ) (min) P WM(H) (min) PWM(L ) V = D V + (1 D )V - FLTR ) L ( PWM ) H ( PWM FLTR FB FB R R V ) D ( V D R // ) R R ( V I error % + - + ´ - + = 1 2 1 1 23 TPS61160, TPS61161 www.ti.com SLVS791E – NOVEMBER 2007 – REVISED JULY 2016 Product Folder Links: TPS61160 TPS61161 Submit Documentation Feedback Copyright © 2007–2016, Texas Instruments Incorporated 8.2.2.1 Design Requirements Example parameters for white LEDs with external PWM dimming: Table 5. Design Parameters for White LEDs with External PWM Dimming DESIGN PARAMETER EXAMPLE VALUE Inductor 10 µH Minimum input voltage 3.6 V Number of series LED 6 LED maximum forward voltage (Vf) 3.2 V Schottky diode forward voltage (Vf) 0.2 V Efficiency 90% Switching frequency (fSW) 600 kHz External PWM output voltage 3 V External PWM frequency 20 kHz Applying Equation 3 and Equation 4 when VIN is 3 V, 6 LEDs output equivalent to VOUT of 19.4 V, the inductor is 10 μH, the Schottky forward voltage is 0.2 V, the maximum output current is 76 mA in typical condition. 8.2.2.2 Detailed Design Procedure 8.2.2.2.1 Choosing Component Values As per SLVA471, the values of RFLTR, CFLTR, R1, R2, and RSET are determined by the system parameters and error tolerance. The main source of LED current error is leakage current from the FB pin. The error gets worse as the LED current decreases. The error due to leakage current is given by Functional Block Diagram, where the impedance seen by the FB pin has a major impact. To reduce error due to the leakage current, the impedance seen by the FB pin needs to be small. Because R2 is much smaller than R1 + RFLTR, R2 must be chosen to be small to minimize the impedance seen by the FB pin. In general, R2 must be chosen to be 1 kΩ or less. If greater accuracy at smaller currents is needed, then R2 must be chosen to be even smaller. (8) Once R2 has been chosen, the value of RSET and R1 + RFLTR can be calculated using Equation 9, Equation 10, Equation 11, and Equation 12. The individual values of R1 and RFLTR can be any combination that sums up to R1 + RFLTR . In general, choosing R1 and RFLTR to be the same value gives a minimum requirement for CFLTR. (9) (10) (11) (12) Finally, CFLTR can be chosen based on the amount of filtering desired or to provide a gradual dimming effect that is popular in many lighting products. At a minimum, CFLTR must be chosen to provide at least 20 dB of attenuation at the PWM frequency. Equation 13 can be used to calculate the minimum capacitor value to provide this attenuation. (13) |
Similar Part No. - TPS61160DRVTG4 |
|
Similar Description - TPS61160DRVTG4 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |