Electronic Components Datasheet Search |
|
ML4836CS Datasheet(PDF) 10 Page - Micro Linear Corporation |
|
ML4836CS Datasheet(HTML) 10 Page - Micro Linear Corporation |
10 / 15 page ML4836 10 Figure 9. Lamp Preheat and Interrupt Timers FUNCTIONAL DESCRIPTION (Continued) RX CX HEAT INHIBIT 0.625 RSET LEA_ENB OR DIMMING LOCKOUT INTERRUPT 10 RX/CX S R Q 1.75/4.65 + – 1.0/1.20 + – 1.25/6.65 + – 9 In this condition, the minimum operating frequency of the ballast is set per equation 5 above. For the IC to be used effectively in dimming ballasts with higher Q output networks a larger CT value and lower RT value can be used, to yield a smaller frequency excursion over the control range (voltage at LFB OUT). The discharge current is set to 7.5mA. The operation of the oscillator is hown in Figure 7. Assuming that IDIS >>IRT: tC DIS VCO T () @´ 600 (9) IC BIAS, UNDER-VOLTAGE LOCKOUT AND THERMAL SHUTDOWN The IC includes a shunt clamp which will limit the voltage at VCC to 14.5V (VCCZ). The IC should be fed with a current limited source, typically derived from the ballast transformer auxiliary winding. When VCC is below VCCZ – 1.1V, the IC draws less than 0.55mA of quiescent current and the outputs are off. This allows the IC to start using a “bleed resistor” from the rectified AC line. The ICC start-up condition is shown in Figure 7. To help reduce ballast cost, the ML4836 includes a temperature sensor which will inhibit ballast operation if the IC’s junction temperature exceeds 140°C. In order to use this sensor in lieu of an external sensor, care should be taken when placing the IC to ensure that it is sensing temperature at the physically appropriate point in the ballast. The ML4836’s die temperature can be estimated with the following equation: TT P C W JA D @+ + ° ( / ) 65 (10) STARTING, RE-START, PREHEAT AND INTERRUPT The lamp starting scenario implemented in the ML4836 is designed to maximize lamp life and minimize ballast heating during lamp out conditions. The circuit in Figure 9 controls the lamp starting scenarios: Filament preheat and lamp out interrupt. CX is charged with a current of IR(SET)/4 and discharged through RX. The voltage at CX is initialized to 0.7V (VBE) at power up. The time for CX to rise to 4.65V is the filament preheat time. During that time, the oscillator charging current (ICHG) is 2.5/RSET. This will produce a high frequency for filament preheat, but will not produce sufficient voltage to ignite the lamp or cause significant glow current. |
Similar Part No. - ML4836CS |
|
Similar Description - ML4836CS |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | 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 |