BIT3713 查看數據表（PDF） - Unspecified
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BIT3713 Datasheet PDF : 11 Pages
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Beyond Innovation Technology Co., Ltd.
Functional Description:
The Power On Initialization: BIT3713 is in an initial
state when TIMER pin voltage is less than 0.3V. An
internal current source charges the external capacitor
connected on TIMER pin determines the operation
timing of BIT3713. This current provides about 20uA
when TIMER pin voltage is less than 0.3V, or about 1uA
when TIMER pin voltage is large than 0.3V. Table 2
lists the states of each key features during TIMER pin
voltage is less than 0.3V.
Table 2 BIT3713 initial states
Pin Number Pin Name
4
CTOSC
8
OUT1
9
OUT2
11
PWMOUT
12
CTPWM
Status
Normally run
Forced to GND level
Forced to VDD level
Floating
Normally run
To Set the Operation Frequency of the 1st High
Frequency PWM Controller: An external capacitor
CCTOSC pin CTOSC determines the frequency as
equation (1)
The frequency of the 1st high frequency PWM controller
is:
FHFPWM
KHF
CCTOSC
,
KHF
8.2e - 5 ............(1)
Or a 100KHz operation PWM control system if an 820pF
capacitor is connected to pin CTOSC. Equation (1) is
valid only when VDD=6V, temperature=30ºC and
frequency (80K ~ 120K)Hz. Fig. 1 shows the
relationship between the frequency of the high frequency
PWM and CTOSC capacitance.
BIT3713
The 1st Latched Off Protection: The ISEN pin may be
used for detecting if the operation is controlled stably
during normal operation. For most of the applications, to
define a staring period in which period no power deliver
to the load side, are necessary. BIT3713 disable the
latched off function when TIMER pin voltage < 2.5V. If
TIMER >2.5V and ISEN < 1.3V for 32 cycles of the 2nd
low frequency PWM, BIT3713 will shut down the output
pins, OUT1 and OUT2 until the system is powered on
again. The detail is as bellow:
During TIMER > 2.5V, the system operates normally when
the ISEN > or < than 1.3V. The lathed off function
performs when ISEN has continuously been kept < 1.3V
for 32 cycles of the 2nd low frequency PWM.
The Output Adjustment and 2nd Latched Off
Protection: The OUTADJ pin may be used for
detecting if the PWM control system operates normally. An
about 60uA current source will charge the INN pin to
adjust the output of CMP while OUTADJ > 2.0V. The
latched off abnormal protection performs while TIMER >
2.5V. If TIMER > 2.5V and OUTADJ > 2.0V for 32
cycles of the 1st high frequency PWM, BIT3713 will shut
down the output pins, OUT1 and OUT2, until the system is
powered on again. The detail is as bellow:
During TIMER > 2.5V, the system operates normally when
the OUTADJ > or < than 2.0V. The lathed off function
performs when OUTADJ has continuously been kept >
2.0V for 32 cycles of the 1st high frequency PWM.
Or, a pulse signal on OUTADJ pin with > 50KHz which
may > 2.0V or < 2.0V. BIT3713 performs latched off
function when TIMER > 2.5V and the pulse signal has
continuously present on OUTADJ pin for 32 cycles of the
1st high frequency PWM.
To Set The Frequency Deviation of High Frequency
PWM During Different Loading Condition: A
connected between GND and LOAD resistor may increase
the operation frequency of CTOSC. An internal switch of
the LOAD pin is closed may be used to change the
frequency of CTOSC before ISEN had been triggered to
larger than 1.3V. In many cases, the resonance
frequency of the load is varied while the load is changed.
For obtaining the better performance, the operation
frequency of the PWM controller must fit to the resonance
frequency of the load. The following diagram shows
how the load resistance changes the 100KHz operation
frequency of CTOSC pin. In above case, CTOSC is
connected by an 820pF capacitor. TheBnoirmTal EopeKration
frequency of high frequency PWM is 100KHz. If a
different frequency says FnDisetcheemsbeetrfo2r0,n2o0rm05al operation.
In BIT3713, the internal switch of the LOAD pin is frozen
to open status whDenCtheCISECN O> 1N.3VT. ROLLED
‘05/12/15
Preliminary
Confidential, for authorized user only
page 5 of 11
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