Silicore SC9106 TEST CIRCUIT 1 2 +5% 0.47uF _ 6.8K 165K +_ 1% S1 8 SC 9106 7 3 6 4 5 191K +_1% S2 0.068uF _ 5% _ A + APPLICATION CIRCUIT R1 1 C1 TIP 0.9uF 560 C5 2 1 8 0.22uF RSL 3 2 RING C4 22uF/35V 29V D1 10K 7 SC9106 3 6 4 5 R2 _1% 165K+ C2 _5% 0.47uF+ 191k _+1% C3 R3 _ 5% 6.9nF+ SP 15K 4 1300:8 APPLICATION NOTE The application circuit illustrates the use of th e UTC9106 device in typical teleph on e tone ringer application. The AC ring er signal vo ltage appears across the TIP and RING inputs of the circuit and is attenuated by capacitor C1 and resistor R1. C1 also prov ides isolation from DC voltage (48V) on the exch anged line. After full wave rectification by th e bridge diode, the waveform is filtered by capacitor C4 to provide a DC supp ly for the tone ringer chip. As this voltage exceeds the initiation voltage (Vsi), oscillation starts. SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 3/5 Silicore SC9106 With th e components shown, th e ou tput frequency chops between 512Hz (f H 1 ) and 640 Hz (f H 2 ) at 10Hz (f L ) rate. The loudspeaker load is coupled th rough a 1300W to 8W transformer. The ou tput coupling capacito r C5 is required with transformer coupled lo ads. When driving a pizeo-ceramic transducer type load , th e coupling C5 and transformer (1300Ω:8Ω) are not required. However, a current limiting resistor is required. The low frequency oscillator oscillates at a rate (FL) controlled by an external resistor (R2) and capacitor (C2). The frequency can be determined using the relation f L =1/1.289 R2* C2. The high frequency oscillates at a f H 1 , f H 2 controlled by an external resistor (R3) and capacitor (C3). The frequency can be determined using the relation f H 1 =1/1.504 R3*C3 and f H 2 = 1/1.203 R3*C3. Pin 2 of the SC9106 allo ws conn ection of external resistor RSL, which is used to program th e slope of the supply current vs supply vo ltage characteristics (see Fig.3), and hence th e supply cu rrent up to the initiation voltage (Vsi). This initiation voltage remains constant independent of RSL. The supply current drawn prior to triggering varies inversely with RSL, decreasing for increasing value of resistance. Thus, increasing the value of RSL, will decrease the amount of AC ringing current required to trigger th e device. As such, longer subscriber loops are possible since less voltage is dropped per unit length of loop wire due to the lower current level. RSL can also be used to co mp ensated for smaller AC coupling capacitors (C5 on application circuit) (higher impedance) to the line which can be used to alter th e ringer equivalence numb er of a tone ringer circuit. The graph in Fig.3 illustrates the variation of supply current with supply voltage of the SC9106. Three curves are drawn to show the variation of in itiation cu rrent with RSL. Curve B ( RSL=6.8k Ω) shows the I-V characteristic fo r SC9106 tone ringer. Cu rve A is a plot with RSL<6.8kΩ and sh ows an increase in the cu rrent drawn up to the initiation voltage Vsi. The I-V characteristic after initiation re mains unchanged . Curve C illustrates the effect of increasing RSL ab ove 6.8kW in itiation current decreases but again current after triggering is un changed. SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 4/5 Silicore SC9106 CHARACTERISTICS CURVES Fig.2 Fig.3 SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 5/5