mc33157dw ON Semiconductor, mc33157dw Datasheet - Page 9

• Manufacturer Part Number: mc33157dw
• Description: Half Bridge Controller And Driver For Industrial Linear Tubes
• Manufacturer: ON Semiconductor

The controller repeats the f SWEEP and the strike sequence until there is a STRIKE signal coming from the external circuit, or until FOUR sequences have been counted.
Following a non strike situation, the controller goes in a full STOP and can be reinitialized by either pulling the V DD pin 1 to ground or by forcing a low to the RESET
pin 9. The controller assumes the lamp has struck when a negative going transient is applied on the STRIKE detection pin 10. On the other hand, in order to avoid false
strike information, the controller force a blank time between the end of t SWEEP and the start of the next sequence.
4.5
3.5
2.5
1.5
0.5
5
4
3
2
1
0
Frequency status
DETECTION
V
V
w
RESET
STRIKE
+V
CSWP
Output
+V
ref
ref
1
0
I = V/ [(R
FSweep
t SF : Sweep Frequency time. This time is given by the RC network built with C SWEEP and R PH .
t SK : Sweep sequence recycle time. This time is derived by integrating a constant DC current in capacitor
C PH. There is a fixed ratio ( ) between the preheating time t PH and strike sequence recycle time t SK .
t fEND : Time during which f = (f ENDSWP ). This time is equal to t SK – t SF .
Z = Lw
Figure 11. TIMING DIAGRAM (no strike conditions)
F2
End of preheating sequence
Figure 12. OUTPUT = f (freq) @ Lc = 1.5 mH, Cs = 6.8 nF
2
F1
+ (L
FSweep
w
F t
t
Blanking 10 ms typ
@ C
SK
)
2
]
PH
F2 F1
t
FEND
= 470 nF
http://onsemi.com
FSweep
MC33157
Frequency (F)
9
F2 F1
SD
FSweep
HIGH
Blanking
F2
I = V/ [(R
SD
LOW
Z @ RLCF
2
Last restrike valid cycle
F3
+ (L
w
– 1/C
w
time
)
2
]