TDA8359J Datasheet, PDF (10/20 Pages) NXP Semiconductors – Full bridge vertical deflection output circuit in LVDMOS

Philips Semiconductors
Full bridge vertical deflection output circuit
in LVDMOS
Product specification
TDA8359J
R_M calculation
Most Philips brand TV signal processors have outputs in
the form of current. This current has to be converted to a
voltage by using resistors at the input of the TDA8359J
(R_CV1 and R_CV2). The differential voltage across these
resistors can be calculated by:
V_{i(dif)(p – p)} = I_{i1(p – p)} × R_CV1 – (–I_{i2(p – p)}) × R_CV2
For calculating the measuring resistor R_M, use the
differential input voltage (V_i(dif)(p-p)). This voltage can also
be measured between pins INA and INB (see Fig.5). The
calculation for R_M is:
R_M = ^V-----i-I⁽--_od--₍-ⁱ-^fp--⁾--⁽_–-^p--_p--^–-₎--^p---⁾
handbook, halfpage
Ii1(p-p)
II(bias)
0
TV SIGNAL
PROCESSOR
C6
2.2 nF
INA ₁
RCV1
2.2 kΩ
C7
2.2 nF
INB ₂
RCV2
2.2 kΩ
Ii2(p-p)
II(bias)
0
MBL366
Fig.5 Input Circuit
Supply voltage calculation
For calculating the minimum required supply voltage,
several specific application parameter values have to be
known. These parameters are the required maximum
(peak) deflection coil current I_coil(peak), the coil impedance
R_coil and L_coil, and the measuring resistance of R_M. The
required maximum (peak) deflection coil current should
also include overscan.
The deflection coil resistance has to be multiplied by 1.2 in
order to take account of hot conditions.
Chapter “Characteristics” supplies values for voltage
losses of the vertical output stage. For the first part of the
scan, the voltage loss is given by V_loss(1). For the second
part of the scan, the voltage loss is given by V_loss(2).
The voltage drop across the deflection coil during scan is
determined by the coil impedance. For the first part of the
scan the inductive contribution and the ohmic contribution
to the total coil voltage drop are of opposite sign, while for
the second part of the scan the inductive part and the
ohmic part have the same sign.
For the vertical frequency the maximum frequency
occurring must be applied to the calculations.
The required power supply voltage V_P for the first part of
the scan is given by:
V_P(1) = I_coil(peak) × (R_coil + R_M)
– L_coil × 2I_coil(peak) × f_vert(max) + V_loss(1)
The required power supply voltage V_P for the second part
of the scan is given by:
V_P(2) = I_coil(peak) × (R_coil + R_M)
+ L_coil × 2I_coil(peak) × f_vert(max) + V_loss(2)
The minimum required supply voltage V_P shall be the
highest of the two values V_P(1) and V_P(2). Spread in supply
voltage and component values also has to be taken into
account.
EXAMPLE
Measured or given values: I_I(bias) = 400 µA; I_i1(p-p) = I_i2(p-p)=
290 µA.
The differential input voltage will be:
V_{i(dif)(p – p)} = 290µA × 2.2kΩ – (–290µA × 2.2kΩ) = 1.27V
2002 Jan 21
10