MC34016 Просмотр технического описания (PDF) - Motorola => Freescale
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MC34016 Datasheet PDF : 16 Pages
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MC34016
DESCRIPTION OF THE CIRCUIT
Throughout this part, please refer to the typical application
of Figure 10. The data given in this chapter refers to typical
data of the characteristics.
DC OPERATION
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ For dc, the MC34016 incorporates four different masks
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ which can be selected via the serial bus interface:
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Bit 4, Reg. 1 Bit 5, Reg. 1 Bit 1, Reg. 2
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ‘DC Mask’ ‘DC Mode’ ‘AGC Ratio’
DC Mask
Selected
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0
0
X
Voltage Regula-
tion Mask
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ X
1
X
Pulse Dial Mask
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1
0
0
Current Regula-
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ tion Mask with
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ AGC Ratio 1:2
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1
0
1
Current Regula-
tion Mask with
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ AGC Ratio 3:5
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ X = don’t care
Voltage Regulation Mask
The voltage regulation mask is the default setting of the
MC34016 after power–up. In this mode, the circuit behaves
as a zener with a series resistor. The line voltage can be
expressed as:
with:
Vline = VBG + (IBG x RDC1) + (Iline x RS)
VBG =1.3 V
IBG = 5.2 µA
RDC1= DC setting resistor of 470 kΩ in the typical
application
Iline = Line current
RS = Slope resistor of 50 Ω in the typical
application
thus: Vline = 3.75 + (50 x Iline)
By choosing different values of RDC1, the zener voltage
can be adjusted to fit country specific requirements. In
Figure 1, a curve shows Vline versus Iline for different RDC1
values.
Pulse Dial Mask
In this mask, the circuit is forced into a very low voltage
drop mode meant for pulse dialing (e.g. make period during
pulse dialing). Pin LAO of the MC34016 sources a current of
5.0 mA in this mode, saturating output transistor Q1. The line
voltage Vline is now determined by the saturation voltage of
Q1 and the dc slope resistor RS:
Vline = VCE(sat)Q1 + (RS x Iline) ≅ 0.1 + (50 x Iline)
Figure 2 shows Vline versus Iline.
Current Regulation Masks
These masks are equal to the voltage regulation mask up
to a knee current. Above this current, the dc slope changes to
a higher value fulfilling requirements such as those in France.
Vline = 3.75 + (RS x Iline) for IAGC < Iknee
Vline = [IBG + (2.5 x (IAGC – Iknee))] x RDC1 +
[VBG + (RS x Iline)] for IAGC > Iknee
6
+ with : IAGC
Iline
x
RS
RAGC
Iknee = 21 µA for AGC ratio 1:2
Iknee = 31 µA for AGC ratio 3:5
With RS = 50 Ω and RAGC = 47 kΩ, and the AGC ratio set
to 3:5, IAGC will equal Iknee at a line current of 29 mA. With the
AGC ratio set to 1:2, the knee occurs at 20 mA. Above these
line currents, it can be derived that the dc slope of the circuit
changes to:
+ ) RSlope
2.5
x
RS x RDC1
RAGC
RS
With the component values mentioned, a slope of 1300 Ω
will occur. Figures 3 and 4 shows Vline versus Iline in the two
current regulation masks for different values of RDC1.
When IAGC reaches 62 µA for AGC ratio 3:5 or 52 µA in
case of AGC ratio 1:2, the MC34016 will enter protection
mode after about 800 ms. In practice this mode occurs only
under overload conditions. In protection mode, the MC34016
decreases the power dissipation in Q1 by drastically
increasing the dc slope starting from Iknee. This results in a
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ reduced line current which remains practically constant over
line voltage. With the equation for Iagc it can be derived that:
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Line Current to Enter
AGC ratio
Protection Mode
Line Current in
Protection Mode
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 3:5
58 mA
29 mA
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1:2
49 mA
20 mA
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Once the MC34016 enters protection mode, it remains
there until the output HKSW is toggled via Bit 0 of Register 1
(on–hook, off–hook).
Supply Voltage VCC
The MC34016 operates from an external supply within a
voltage range of 3.0 to 5.5 V. The current consumption with
all bits set to 0, equals 3.0 mA at 3.0 V and 3.5 mA at 5.5 V.
AC SET IMPEDANCE
The MC34016 offers two possibilities for the adjustment of
the ac set impedance. Either a passive or an active set
impedance can be obtained.
Passive Set Impedance
In this application, the set impedance is formed by the ac
impedance of the circuit itself in parallel with resistor RSET
and capacitor CSET. An equivalent network equals:
RDC1
RDC1 x CM x RS
RSET
CM
RS
CSET
MOTOROLA ANALOG IC DEVICE DATA
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